CVE & CISA-KEV Catalog

CVE-2026-90439

MEDIUM
6.5
CVSS v3
NVD

Description

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_v3_module module. When using HTTP/3 with OpenSSL versions <= OpenSSL 3.5.0 under certain configurations, a limited heap buffer overflow could happen while processing a TLS handshake. This can happen in a non-deterministic manner that is beyond the attacker's control. This may cause a heap buffer overflow in the NGINX worker process leading to a restart and/or limited data corruption. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or limited data corruption. 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.

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

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CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityLow
AvailabilityLow

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

Exploit Intelligence

EPSS data unavailable for this CVE.

References

Other references1

Related Vulnerabilities

Other CWE-122 (Heap-based Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2015-3113Critical9.8100%KEVFix
CVE-2020-25687Medium5.987%-Fix
CVE-2009-3459High8.887%KEVFix
CVE-2021-21017High8.886%KEV-
CVE-2020-25683Medium5.986%-Fix
CVE-2023-27997Critical9.886%KEV + Ransom-

Common questions

How do I fix CVE-2026-90439?

No published fix for CVE-2026-90439 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

How severe is CVE-2026-90439?

CVE-2026-90439 has a CVSS v3 base score of 6.5, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-18.