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VulnerabilityPublished

CVE-2026-26310: envoyproxy envoy · Improper Input Validation

Affects envoyproxy envoySource CVE Database V5

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Not known to be exploited · CVSS 5.9 Medium · fixed in 1.37.1 : update envoyproxy envoy when convenient.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score
5.9Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 35% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.37.1, 1.36.5, 1.35.9 +1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 10 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade envoy to 1.37.1, 1.36.5, 1.35.9 or 1.34.13; envoyproxy/envoy to 1.34.13.

Affected software

ProductAffectedFixed in
envoyproxyenvoyAffected
  • >=1.37.0 <1.37.1
Fixed in
  • 1.37.1
envoyproxyenvoyAffected
  • >=1.36.0 <1.36.5
Fixed in
  • 1.36.5
envoyproxyenvoyAffected
  • >=1.35.0 <1.35.9
Fixed in
  • 1.35.9
envoyproxyenvoyAffected
  • <1.34.13
Fixed in
  • 1.34.13
GitHubenvoyproxy/envoypkg:github/envoyproxy/envoyOther threatsAffected
  • <1.34.13
Fixed in
  • 1.34.13

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Organizations should upgrade affected Envoy instances to the patched versions 1.37.1, 1.36.5, 1.35.8, or 1.34.13 as soon as possible to eliminate the vulnerability. In environments where immediate upgrade is not feasible, network-level mitigations can be applied to restrict or filter traffic containing scoped IPv6 addresses to Envoy instances, reducing exposure to crafted packets that trigger the crash. Monitoring Envoy logs and metrics for unexpected crashes or restarts can help detect exploitation attempts. Implementing redundancy and failover mechanisms for Envoy proxies can mitigate the impact of potential DoS conditions. Additionally, reviewing and hardening network segmentation and access controls to limit exposure of Envoy data plane components to untrusted networks will reduce the attack surface. Security teams should also keep abreast of any emerging exploit reports or proof-of-concept code to adjust defenses accordingly.

Description

Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, calling Utility::getAddressWithPort with a scoped IPv6 addresses causes a crash. This utility is called in the data plane from the original_src filter and the dns filter. This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.

References

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