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 1.20% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-93479High confidence
NGINX map directive and regex matching vulnerability
F5 · NGINX Plus
Official source article: F5 K000162607 ↗. Check the applicable product and release in the original source.
9.2CriticalCVSS 4.0
Patch only the product branches with a verified fix
Fix availability varies by productCritical 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 23 structured product or package states 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 severityCritical→Operational priority:Critical, unchanged from published severity.unchanged
Compensating controls
- Apply the linked authoritative mitigation while planning the permanent fix.
- 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 Plus and falls inside the recorded affected range.
- Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
- 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 23 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
- Red Hat Product Security: 22 affected or under-investigation product states without a fixed product state in the same current advisory
- Debian Security Tracker: 1 affected package state with no published fix
Distribution package intelligence
5 package statesRelease-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.
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 |
|---|---|---|---|---|
| Debian trixietrixie · source | nginx | Vendor fix publishedDebian records a fixed source-package version for this release. | 1.26.3-3+deb13u10 | Debian Security Tracker ↗Source updated 30 Oct 2026 |
| Debian bookwormbookworm · source | nginx | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 30 Oct 2026 |
| Debian forkyforky · source | nginx | Vendor fix publishedDebian records a fixed source-package version for this release. | 1.30.4-8 | Debian Security Tracker ↗Source updated 30 Oct 2026 |
| Debian sidsid · source | nginx | Vendor fix publishedDebian records a fixed source-package version for this release. | 1.30.4-8 | Debian Security Tracker ↗Source updated 30 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | nginx | Vendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree. | 1.24.0-2ubuntu7.19 | Canonical Ubuntu Security ↗Source updated 30 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-2026-93479 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitynginx: NGINX map directive and regex matching vulnerability
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 as a component of Red Hat Enterprise Linux 9
- Summary
- A flaw was found in NGINX. An unauthenticated attacker can exploit this vulnerability by sending specially crafted HTTP requests when the `map` directive uses regular expression (regex) matching and references regex capture variables before referencing the map output variable. This can lead to a heap buffer overflow, which may allow for arbitrary code execution on systems where Address Space Layout Randomization (ASLR) is disabled or bypassed. Additionally, this flaw can cause a denial-of-service (DoS) due to the NGINX worker process restarting.
- Remediation
- To mitigate this vulnerability, do not use unnamed captures. Use named captures instead and only use them in the same block with the regex match. Red Hat recommends updating nginx to the latest version when a fix is available. According to F5, the following versions contain the fix: 1.31.7, 1.30.6
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 23 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Fix availability varies by product01
What, why and how
A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and the root directive or access log format references the map's regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
What
A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and the root directive or access log format references the map's regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
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 a network path may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.
What
A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and the root directive or access log format references the map's regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
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 a network path may attempt exploitation without authentication or user interaction. 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
- a network path → Heap-based Buffer Overflow → execute code or commands in the affected security context
- Attack surface
- Network
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- None
- Attack complexity
- High: exploitation depends on specific conditions
- Security boundary
- Not a CVSS 4.0 base metric
- 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:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/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.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VIHighVulnerable-system integrity: A successful attack can cause a major loss.VAHighVulnerable-system availability: A successful attack can cause a major loss.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.- 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
- 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 as a component of Red Hat Enterprise Linux 9
- nginx-all-modules as a component of Red Hat Enterprise Linux 9
- nginx-core as a component of Red Hat Enterprise Linux 9
- nginx-filesystem as a component of Red Hat Enterprise Linux 9
- nginx-mod-devel as a component of Red Hat Enterprise Linux 9
- nginx-mod-http-image-filter as a component of Red Hat Enterprise Linux 9
- nginx-mod-http-perl as a component of Red Hat Enterprise Linux 9
- nginx-mod-http-xslt-filter as a component of Red Hat Enterprise Linux 9
- nginx-mod-mail as a component of Red Hat Enterprise Linux 9
- nginx-mod-stream as a component of Red Hat Enterprise Linux 9
- nginx.src as a component of Red Hat Enterprise Linux 9
- 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
- To mitigate this vulnerability, do not use unnamed captures. Use named captures instead and only use them in the same block with the regex match. Red Hat recommends updating nginx to the latest version when a fix is available. According to F5, the following versions contain the fix: 1.31.7, 1.30.6
04
Evidence and provenance
Published 14 Oct 2026 · Last source change 29 Oct 2026, 16:59 UTC · CWE-122 · Heap-based Buffer Overflow
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-10-15
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-101114
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD awaiting enrichment
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
- ENISA EUVD mappingEUVD-2026-101114 was added to the official ENISA EUVD mapping for this CVE.ENISA EUVD ↗
- Before
- not recorded
- After
- {"euvdId":"EUVD-2026-101114"}
- Catalogue recordCVE added to the BlackTree catalogue.CNA ↗
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.