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 0.34% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-42926High confidence
NGINX ngx_http_proxy_v2_module vulnerability
F5 · NGINX Open Source
Official source article: F5 K000161131 ↗. Check the applicable product and release in the original source.
6.3MediumCVSS 4.0
Scheduled
Patch availableMedium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityMedium→Operational priority:Medium, unchanged from published severity.unchanged
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 F5 NGINX Open Source 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.
Distribution package intelligence
4 package statesRelease-specific package status
Debian findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
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 | nginx | Not affectedDebian marks this release not affected (fixed-version marker 0). | Not published in this feed | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian bookwormbookworm · source | nginx | Not affectedDebian marks this release not affected (fixed-version marker 0). | Not published in this feed | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian forkyforky · source | nginx | Vendor fix publishedDebian records a fixed source-package version for this release. | 1.30.0-4 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian sidsid · source | nginx | Vendor fix publishedDebian records a fixed source-package version for this release. | 1.30.0-4 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
Direct vendor intelligence
1 currentAuthoritative 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.
CVE-2026-42926 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitynginx: NGINX Open Source: Data injection via HTTP/2 proxy configuration
The vendor explicitly identifies these products as affected by this CVE.
- nginx as a component of Red Hat Enterprise Linux 10
- nginx-all-modules as a component of Red Hat Enterprise Linux 10
- nginx-core as a component of Red Hat Enterprise Linux 10
- nginx-filesystem as a component of Red Hat Enterprise Linux 10
- nginx-mod-devel as a component of Red Hat Enterprise Linux 10
- nginx-mod-http-image-filter as a component of Red Hat Enterprise Linux 10
- nginx-mod-http-perl as a component of Red Hat Enterprise Linux 10
- nginx-mod-http-xslt-filter as a component of Red Hat Enterprise Linux 10
- nginx-mod-mail as a component of Red Hat Enterprise Linux 10
- nginx-mod-stream as a component of Red Hat Enterprise Linux 10
- nginx.src as a component of Red Hat Enterprise Linux 10
- nginx-all-modules (nginx:1.24) as a component of Red Hat Enterprise Linux 8
- Summary
- A flaw was found in NGINX Open Source. When NGINX is configured to proxy HTTP/2 traffic and uses `proxy_set_body`, a remote attacker may be able to inject malicious data into the upstream peer. This could lead to unintended data manipulation or bypass of security controls.
- Remediation
- For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
Patch available01
What, why and how
When NGINX Open Source is configured to proxy HTTP/2 traffic by setting proxy_http_version to 2, and also uses proxy_set_body, an attacker may be able to inject frame headers and payload bytes to the upstream peer. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
What
When NGINX Open Source is configured to proxy HTTP/2 traffic by setting proxy_http_version to 2, and also uses proxy_set_body, an attacker may be able to inject frame headers and payload bytes to the upstream peer. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Why
The product does not properly encode or decode the data, resulting in unexpected values.
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
When NGINX Open Source is configured to proxy HTTP/2 traffic by setting proxy_http_version to 2, and also uses proxy_set_body, an attacker may be able to inject frame headers and payload bytes to the upstream peer. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Why
The product does not properly encode or decode the data, resulting in unexpected values.
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.
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
- a network path → Encoding Error → 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
- Not a CVSS 4.0 base metric
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-172 ↗
CWE-172: Encoding Error. The product does not properly encode or decode the data, resulting in unexpected values.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:NCommon Vulnerability Scoring System 4.0: 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.ATPresentAttack requirements: A particular deployment or execution condition must be present.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCNoneVulnerable-system confidentiality: No direct loss is represented by this metric.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SILowSubsequent-system integrity: A successful attack can cause a limited loss.SANoneSubsequent-system availability: No direct loss is represented by this metric.- 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.
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. - Patch available
- Affected
- nginx as a component of Red Hat Enterprise Linux 10
- nginx-all-modules as a component of Red Hat Enterprise Linux 10
- nginx-core as a component of Red Hat Enterprise Linux 10
- nginx-filesystem as a component of Red Hat Enterprise Linux 10
- nginx-mod-devel as a component of Red Hat Enterprise Linux 10
- nginx-mod-http-image-filter as a component of Red Hat Enterprise Linux 10
- nginx-mod-http-perl as a component of Red Hat Enterprise Linux 10
- nginx-mod-http-xslt-filter as a component of Red Hat Enterprise Linux 10
- nginx-mod-mail as a component of Red Hat Enterprise Linux 10
- nginx-mod-stream as a component of Red Hat Enterprise Linux 10
- nginx.src as a component of Red Hat Enterprise Linux 10
- nginx-all-modules (nginx:1.24) as a component of Red Hat Enterprise Linux 8
- nginx-filesystem (nginx:1.24) as a component of Red Hat Enterprise Linux 8
- nginx-mod-devel (nginx:1.24) as a component of Red Hat Enterprise Linux 8
- nginx-mod-http-image-filter (nginx:1.24) as a component of Red Hat Enterprise Linux 8
- nginx-mod-http-perl (nginx:1.24) as a component of Red Hat Enterprise Linux 8
- nginx-mod-http-xslt-filter (nginx:1.24) as a component of Red Hat Enterprise Linux 8
- nginx-mod-mail (nginx:1.24) as a component of Red Hat Enterprise Linux 8
- nginx-mod-stream (nginx:1.24) as a component of Red Hat Enterprise Linux 8
- nginx.src (nginx:1.24) as a component of Red Hat Enterprise Linux 8
- nginx (nginx:1.24) as a component of Red Hat Enterprise Linux 8
- nginx as a component of Red Hat Enterprise Linux 9
- nginx-all-modules as a component of Red Hat Enterprise Linux 9
- nginx-all-modules (nginx:1.24) as a component of Red Hat Enterprise Linux 9
- nginx-all-modules (nginx:1.26) as a component of Red Hat Enterprise Linux 9
- nginx-core as a component of Red Hat Enterprise Linux 9
- nginx-core (nginx:1.24) as a component of Red Hat Enterprise Linux 9
- nginx-core (nginx:1.26) as a component of Red Hat Enterprise Linux 9
- nginx-filesystem as a component of Red Hat Enterprise Linux 9
- nginx-filesystem (nginx:1.24) as a component of Red Hat Enterprise Linux 9
- and 24 more
- Fixed
- Action
- For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
- Workaround
- No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 13 May 2026 · Last source change 13 May 2026, 16:16 UTC · CWE-172 · Encoding Error
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-2026-30006
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD enriched
Core structured fields are present and their contributing authorities are shown above.
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.