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VulnerabilityPublished

CVE-2026-50572: envoyproxy envoy · Use After Free

Affects envoyproxy envoySource CVE Database V5

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Not known to be exploited · CVSS 5.9 Medium · fixed in 1.39.1 : update envoyproxy envoy when convenient.

Data as of 5 Nov 2026, 00:01 UTC

CVSS 3.1 base score
5.9Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.6% chance of exploitation in 30 days – higher than 52% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.39.1, 1.38.4, 1.37.6 +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 21 Sep 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 5 Nov 2026.

What to do

Upgrade envoy and envoyproxy/envoy to 1.39.1, 1.38.4, 1.37.6 or 1.36.10.

Affected software

ProductAffectedFixed in
envoyproxyenvoyAffected
  • >=1.39.0 <1.39.1
Fixed in
  • 1.39.1
envoyproxyenvoyAffected
  • >=1.38.0 <1.38.4
Fixed in
  • 1.38.4
envoyproxyenvoyAffected
  • >=1.37.0 <1.37.6
Fixed in
  • 1.37.6
envoyproxyenvoyAffected
  • <1.36.10
Fixed in
  • 1.36.10
GitHubenvoyproxy/envoypkg:github/envoyproxy/envoyOther threatsAffected
  • <1.36.10
  • >=1.37.0 <1.37.6
  • >=1.38.0 <1.38.4
  • >=1.39.0 <1.39.1
Fixed in
  • 1.36.10
  • 1.37.6
  • 1.38.4
  • 1.39.1

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

AI-suggested

Upgrade Envoy to versions 1.36.10, 1.37.6, 1.38.4, or 1.39.1 or later where this issue is fixed. No other mitigation or temporary workaround is indicated by the advisory.

Description

CVE-2026-50572 is a use-after-free vulnerability in the Envoy proxy's HTTP external-authorization client. It occurs when a stale request callback is retained after a request rejection, leading to a process crash when the callback is invoked after its owner is destroyed. This issue affects specific versions prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1 and is fixed in these versions.

References

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