Full vulnerability report · 2026

CVE-2026-64102High confidence

RDMA/siw: Reject MPA FPDU length underflow before signed receive math

Linux · Linux

9.8CriticalCVSS 3.1

Recommended action

Patch only the product branches with a verified fix

Critical technical impact with a remotely reachable, unauthenticated path; no CISA KEV confirmation is currently recorded. Verified remediation exists for at least one product or source, but 20 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product

Operational reassessment

Published severity in operational context

Open reassessment dashboard →

Published severityCriticalOperational priority:Critical, unchanged from published severity.unchanged

Evidence used

No CISA KEV confirmation is currently recorded.
The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
EPSS is 0.50% for the current model date.

Compensating controls

Validate the affected product branch and deploy the verified fixed release.
Restrict the affected network interface to trusted sources where business-safe.
Monitor vendor guidance and exploitation sources for a material change.

Verification

Confirm that the asset runs Linux Linux and falls inside the recorded affected range.
Verify the installed build against the product-specific fixed version after deployment.
Validate exposure, authentication requirements and compensating controls in the actual environment.
Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 20 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Canonical Ubuntu Security: 20 affected package states with no published fix

Distribution package intelligence

Release-specific package status

Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

24 package states

Package result overrides the generic status

BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 20 affected package states shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.

Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution release	Source package	Vendor state	Fixed version	Evidence
Debian trixietrixie · source	`linux`	Vendor fix publishedDebian records a fixed source-package version for this release.	`6.12.94-1`	Debian Security Tracker ↗Source updated 7 Oct 2026
Debian bookwormbookworm · source	`linux`	Vendor fix publishedDebian records a fixed source-package version for this release.	`6.1.176-1`	Debian Security Tracker ↗Source updated 7 Oct 2026
Debian forkyforky · source	`linux`	Vendor fix publishedDebian records a fixed source-package version for this release.	`7.0.12-1`	Debian Security Tracker ↗Source updated 7 Oct 2026
Debian sidsid · source	`linux`	Vendor fix publishedDebian records a fixed source-package version for this release.	`7.0.12-1`	Debian Security Tracker ↗Source updated 7 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-aws`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-azure`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-azure-fde`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-azure-nvidia`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-gcp`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-gke`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-gkeop`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-ibm`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-lowlatency`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-nvidia`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-nvidia-lowlatency`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-nvidia-tegra`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-oem-6.11`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-oracle`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-raspi`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-raspi-realtime`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-realtime`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-riscv`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-xilinx`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical Ubuntu Security ↗Source updated 6 Oct 2026

Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

2 current

CVE-2026-64102 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitykernel: RDMA/siw: Reject MPA FPDU length underflow before signed receive math

22 known affected

The vendor explicitly identifies these products as affected by this CVE.

kernel-rt as a component of Red Hat Enterprise Linux 9
kernel-rt-core as a component of Red Hat Enterprise Linux 9
kernel-rt-debug as a component of Red Hat Enterprise Linux 9
kernel-rt-debug-core as a component of Red Hat Enterprise Linux 9
kernel-rt-debug-devel as a component of Red Hat Enterprise Linux 9
kernel-rt-debug-devel-matched as a component of Red Hat Enterprise Linux 9
kernel-rt-debug-kvm as a component of Red Hat Enterprise Linux 9
kernel-rt-debug-modules as a component of Red Hat Enterprise Linux 9
kernel-rt-debug-modules-core as a component of Red Hat Enterprise Linux 9
kernel-rt-debug-modules-extra as a component of Red Hat Enterprise Linux 9
kernel-rt-debug-modules-internal as a component of Red Hat Enterprise Linux 9
kernel-rt-debug-modules-partner as a component of Red Hat Enterprise Linux 9

Summary: A flaw was found in the Linux kernel's Soft-iWARP (siw) component for Remote Direct Memory Access (RDMA). A remote attacker can send a specially crafted iWARP Fast Path Data Unit (FPDU) with a manipulated length field. This manipulation causes an integer underflow, leading to a use-after-free vulnerability. Successful exploitation of this flaw could result in a system crash, leading to a Denial of Service (DoS).
Remediation: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available.

CVE-2026-64102 · CSAF 2.0 · revision 12 · interimSUSE Product Security TeamCVE-2026-64102

247 known affected

The vendor explicitly identifies these products as affected by this CVE.

kernel-default as component of SUSE Linux Enterprise Desktop 15 SP7
kernel-default-extra as component of SUSE Linux Enterprise Desktop 15 SP7
kernel-source as component of SUSE Linux Enterprise Desktop 15 SP7
cluster-md-kmp-default as component of SUSE Linux Enterprise High Availability Extension 15 SP7
dlm-kmp-default as component of SUSE Linux Enterprise High Availability Extension 15 SP7
gfs2-kmp-default as component of SUSE Linux Enterprise High Availability Extension 15 SP7
kernel-default as component of SUSE Linux Enterprise High Availability Extension 15 SP7
kernel-source as component of SUSE Linux Enterprise High Availability Extension 15 SP7
ocfs2-kmp-default as component of SUSE Linux Enterprise High Availability Extension 15 SP7
kernel-default as component of SUSE Linux Enterprise High Availability Extension 16.0
kernel-source as component of SUSE Linux Enterprise High Availability Extension 16.0
kernel-default as component of SUSE Linux Enterprise High Performance Computing 15 SP2

Summary: In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: Reject MPA FPDU length underflow before signed receive math A malicious connected siw peer can send an iWARP FPDU whose MPA length field (c_hdr->mpa_len, 16 bit big-endian, peer-controlled) is smaller than the fixed DDP/RDMAP header for the announced opcode. Soft-iWARP parses the full header in siw_get_hdr() based on iwarp_pktinfo[opcode] .hdr_len, but never compares mpa_len against that header length. siw_tcp_rx_data() then derives srx->fpdu_part_rem = be16_to_cpu(mpa_len) - fpdu_part_rcvd + MPA_HDR_SIZE; where fpdu_part_rcvd equals iwarp_pktinfo[opcode].hdr_len at this point. For a tagged WRITE (hdr_len 16, MPA_HDR_SIZE 2) the smallest on-wire mpa_len of 0 yields fpdu_part_rem = -14, and any mpa_len below hdr_len - MPA_HDR_SIZE underflows to a negative int. The signed value then flows into siw_proc_write()/siw_proc_rresp() as bytes = min(srx->fpdu_part_rem, srx->skb_new); is handed to siw_check_mem() as an int len (whose interval check addr + len > mem->va + mem->len is satisfied for a valid base when len is negative), and reaches siw_rx_data() -> siw_rx_kva() / siw_rx_umem() -> skb_copy_bits() as a signed copy length. The header copy branch in skb_copy_bits() promotes that to size_t, producing a multi-gigabyte read. KASAN under a KUnit harness that drives the real kernel TCP receive path -- a loopback AF_INET socketpair, the malformed FPDU written via kernel_sendmsg, sk_data_ready firing in softirq, tcp_read_sock dispatching to siw_tcp_rx_data -- reports: BUG: KASAN: use-after-free in skb_copy_bits+0x284/0x480 Read of size 4294967295 at addr ffff888... Call Trace: skb_copy_bits siw_rx_kva siw_rx_data siw_check_mem siw_proc_write siw_tcp_rx_data __tcp_read_sock siw_qp_llp_data_ready tcp_data_ready tcp_data_queue Add the missing invariant at the earliest point where the peer header is fully assembled. iwarp_pktinfo[*].hdr_len - MPA_HDR_SIZE is exactly the value the siw transmitter uses as the minimum mpa_len for each opcode (drivers/infiniband/sw/siw/siw_qp.c:33), so this matches the protocol contract. Out-of-range FPDUs terminate the connection with TERM_ERROR_LAYER_LLP / LLP_ETYPE_MPA / LLP_ECODE_FPDU_START -- which is RFC 5044 Section 8 error code 3 ("Marker and ULPDU Length fields do not agree on the start of an FPDU"), the correct framing-error class for this inconsistency.
Remediation: To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

Recommended actionPatch only the product branches with a verified fix

Fix availability varies by product

What, why and how

In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: Reject MPA FPDU length underflow before signed receive math A malicious connected siw peer can send an iWARP FPDU whose MPA length field (c_hdr->mpa_len, 16 bit big-endian, peer-controlled) is smaller than the fixed DDP/RDMAP header for the announced opcode. Soft-iWARP parses the full header in siw_get_hdr() based on iwarp_pktinfo[opcode] .hdr_len, but never compares mpa_len against that header length. siw_tcp_rx_data() then derives srx->fpdu_part_rem = be16_to_cpu(mpa_len) - fpdu_part_rcvd + MPA_HDR_SIZE; where fpdu_part_rcvd equals iwarp_pktinfo[opcode].hdr_len at this point. For a tagged WRITE (hdr_len 16, MPA_HDR_SIZE 2) the smallest on-wire mpa_len of 0 yields fpdu_part_rem = -14, and any mpa_len below hdr_len - MPA_HDR_SIZE underflows to a negative int. The signed value then flows into siw_proc_write()/siw_proc_rresp() as bytes = min(srx->fpdu_part_rem, srx->skb_new); is handed to siw_check_mem() as an int len (whose interval check addr + len > mem->va + mem->len is satisfied for a valid base when len is negative), and reaches siw_rx_data() -> siw_rx_kva() / siw_rx_umem() -> skb_copy_bits() as a signed copy length. The header copy branch in skb_copy_bits() promotes that to size_t, producing a multi-gigabyte read. KASAN under a KUnit harness that drives the real kernel TCP receive path -- a loopback AF_INET socketpair, the malformed FPDU written via kernel_sendmsg, sk_data_ready firing in softirq, tcp_read_sock dispatching to siw_tcp_rx_data -- reports: BUG: KASAN: use-after-free in skb_copy_bits+0x284/0x480 Read of size 4294967295 at addr ffff888... Call Trace: skb_copy_bits siw_rx_kva siw_rx_data siw_check_mem siw_proc_write siw_tcp_rx_data __tcp_read_sock siw_qp_llp_data_ready tcp_data_ready tcp_data_queue Add the missing invariant at the earliest point where the peer header is fully assembled. iwarp_pktinfo[*].hdr_len - MPA_HDR_SIZE is exactly the value the siw transmitter uses as the minimum mpa_len for each opcode (drivers/infiniband/sw/siw/siw_qp.c:33), so this matches the protocol contract. Out-of-range FPDUs terminate the connection with TERM_ERROR_LAYER_LLP / LLP_ETYPE_MPA / LLP_ECODE_FPDU_START -- which is RFC 5044 Section 8 error code 3 ("Marker and ULPDU Length fields do not agree on the start of an FPDU"), the correct framing-error class for this inconsistency.

What

Why

The product reads data past the end, or before the beginning, of the intended buffer.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Why

The product reads data past the end, or before the beginning, of the intended buffer.

How

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path: a network path → Out-of-bounds Read → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface: Network
Privileges required: None: unauthenticated exploitation is possible
User interaction: None
Attack complexity: Low: no specialised conditions are recorded
Security boundary: Unchanged: impact remains within the vulnerable component's security authority
Weakness ? CWE means Common Weakness Enumeration: a standard category for the underlying weakness.: CWE-125 ↗
CWE-125: Out-of-bounds Read. The product reads data past the end, or before the beginning, of the intended buffer.
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land: No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.

NetworkUnauthenticatedCWE-125

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-45787Official EUVD mapping

0 linked advisory records.

Official EUVD record ↗

BSI · German · WID-SEC-2026-2403Linux Kernel: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff

Ein Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen, möglicherweise Sicherheitsmaßnahmen zu umgehen, einen Denial-of-Service-Zustand herbeizuführen oder vertrauliche Informationen offenzulegen.