Evidence used
- No CISA KEV confirmation is currently recorded.
- Exploitation requires an existing local or physical foothold with privileges.
- EPSS is 1.42% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2024
CVE-2024-21885High confidence
Xorg-x11-server: heap buffer overflow in xisenddevicehierarchyevent
Unknown · Unknown
Official source article: Red Hat RHSA-2024:0320 ↗. Check the applicable product and release in the original source.
7.8HighCVSS 3.1
Patch only the product branches with a verified fix
Fix availability varies by productHigh technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:Medium, lowered one band.downgradedsince 6 Nov 2025
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict local access and enforce least privilege on affected hosts.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs Unknown Unknown 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.
Remediation availability differs by product scope
Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
- Debian Security Tracker: 1 affected package state with no published fix
Distribution package intelligence
15 package statesRelease-specific package status
Alpine, Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
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 1 affected package state 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 |
|---|---|---|---|---|
| Alpine v3.23v3.23 · community | xorg-server | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 21.1.11-r0 | Alpine Security Database ↗Source updated 11 Sep 2026 |
| Alpine v3.23v3.23 · community | xwayland | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 23.2.4-r0 | Alpine Security Database ↗Source updated 11 Sep 2026 |
| Alpine v3.22v3.22 · community | xorg-server | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 21.1.11-r0 | Alpine Security Database ↗Source updated 11 Sep 2026 |
| Alpine v3.22v3.22 · community | xwayland | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 23.2.4-r0 | Alpine Security Database ↗Source updated 11 Sep 2026 |
| Alpine v3.21v3.21 · community | xorg-server | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 21.1.11-r0 | Alpine Security Database ↗Source updated 19 Aug 2026 |
| Alpine v3.21v3.21 · community | xwayland | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 23.2.4-r0 | Alpine Security Database ↗Source updated 19 Aug 2026 |
| Debian trixietrixie · source | xorg-server | Vendor fix publishedDebian records a fixed source-package version for this release. | 2:21.1.11-1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian trixietrixie · source | xwayland | Vendor fix publishedDebian records a fixed source-package version for this release. | 2:23.2.4-1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian bookwormbookworm · source | xorg-server | Vendor fix publishedDebian records a fixed source-package version for this release. | 2:21.1.7-3+deb12u5 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian bookwormbookworm · source | xwayland | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian forkyforky · source | xorg-server | Vendor fix publishedDebian records a fixed source-package version for this release. | 2:21.1.11-1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian forkyforky · source | xwayland | Vendor fix publishedDebian records a fixed source-package version for this release. | 2:23.2.4-1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian sidsid · source | xorg-server | Vendor fix publishedDebian records a fixed source-package version for this release. | 2:21.1.11-1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian sidsid · source | xwayland | Vendor fix publishedDebian records a fixed source-package version for this release. | 2:23.2.4-1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | xwayland | Vendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree. | 2:23.2.4-1 | Canonical Ubuntu Security ↗Source updated 5 Oct 2026 |
High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Fix availability varies by product01
What, why and how
A flaw was found in X.Org server. In the XISendDeviceHierarchyEvent function, it is possible to exceed the allocated array length when certain new device IDs are added to the xXIHierarchyInfo struct. This can trigger a heap buffer overflow condition, which may lead to an application crash or remote code execution in SSH X11 forwarding environments.
What
A flaw was found in X.Org server. In the XISendDeviceHierarchyEvent function, it is possible to exceed the allocated array length when certain new device IDs are added to the xXIHierarchyInfo struct. This can trigger a heap buffer overflow condition, which may lead to an application crash or remote code execution in SSH X11 forwarding environments.
Why
A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
How
An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may execute code or commands in the affected security context.
What
A flaw was found in X.Org server. In the XISendDeviceHierarchyEvent function, it is possible to exceed the allocated array length when certain new device IDs are added to the xXIHierarchyInfo struct. This can trigger a heap buffer overflow condition, which may lead to an application crash or remote code execution in SSH X11 forwarding environments.
Why
A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
How
An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may execute code or commands in the affected security context.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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
- local access → Heap-based Buffer Overflow → execute code or commands in the affected security context
- Attack surface
- Local
- Privileges required
- Low: a basic authenticated account is required
- 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-122 ↗
CWE-122: Heap-based Buffer Overflow. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level 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
- After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Fix availability varies by product
- Affected
- < 21.1.11, < 23.2.4
- Fixed
- 21.1.11 < *, 23.2.4 < *
- Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION: 0:1.1.0-25.el6_10.13 < *
- Red Hat Enterprise Linux 7: 0:1.20.4-27.el7_9 < *, 0:1.8.0-31.el7_9 < *
- Red Hat Enterprise Linux 8: 0:1.13.1-2.el8_9.7 < *, 0:1.20.11-22.el8 < *, 0:21.1.3-15.el8 < *
- Red Hat Enterprise Linux 8.2 Advanced Update Support: 0:1.9.0-15.el8_2.9 < *
- Red Hat Enterprise Linux 8.2 Telecommunications Update Service: 0:1.9.0-15.el8_2.9 < *
- Red Hat Enterprise Linux 8.2 Update Services for SAP Solutions: 0:1.9.0-15.el8_2.9 < *
- Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support: 0:1.11.0-8.el8_4.8 < *
- Red Hat Enterprise Linux 8.4 Telecommunications Update Service: 0:1.11.0-8.el8_4.8 < *
- Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions: 0:1.11.0-8.el8_4.8 < *
- Red Hat Enterprise Linux 8.6 Extended Update Support: 0:1.12.0-6.el8_6.9 < *
- Red Hat Enterprise Linux 8.8 Extended Update Support: 0:1.12.0-15.el8_8.7 < *
- Red Hat Enterprise Linux 9: 0:1.13.1-3.el9_3.6 < *, 0:1.20.11-24.el9 < *, 0:22.1.9-5.el9 < *
- Red Hat Enterprise Linux 9.0 Extended Update Support: 0:1.11.0-22.el9_0.8 < *
- Red Hat Enterprise Linux 9.2 Extended Update Support: 0:1.12.0-14.el9_2.5 < *
- Action
- Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
- Workaround
- No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04
Evidence and provenance
Published 28 Feb 2024 · Last source change 6 Nov 2025, 20:53 UTC · CWE-122 · Heap-based Buffer Overflow
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2024-19496
Product sourceUnavailable
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD not scheduled
Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.
Material change intelligence
View recent updates ↗What changed after publication
No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.
CVE published
Fixed release or patch reference recorded
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.