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VulnerabilityPublished

CVE-2026-48706: envoyproxy envoy · Classic Buffer Overflow

Affects envoyproxy envoySource CVE Database V5

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Not known to be exploited · CVSS 5.9 Medium · fixed in 1.38.3 : update envoyproxy envoy when convenient.

Data as of 7 Nov 2026, 23:24 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 49% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.38.3, 1.37.5, 1.36.9 +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 26 Jun 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 8 Nov 2026.

What to do

Upgrade envoy and envoyproxy/envoy to 1.38.3, 1.37.5, 1.36.9 or 1.35.13.

Affected software

ProductAffectedFixed in
envoyproxyenvoyAffected
  • >=1.38.0 <1.38.3
Fixed in
  • 1.38.3
envoyproxyenvoyAffected
  • >=1.37.0 <1.37.5
Fixed in
  • 1.37.5
envoyproxyenvoyAffected
  • >=1.36.0 <1.36.9
Fixed in
  • 1.36.9
envoyproxyenvoyAffected
  • >=1.34.0 <1.35.13
Fixed in
  • 1.35.13
GitHubenvoyproxy/envoypkg:github/envoyproxy/envoyOther threatsAffected
  • <1.35.13
  • <1.36.9
  • <1.37.5
  • <1.38.3
Fixed in
  • 1.35.13
  • 1.36.9
  • 1.37.5
  • 1.38.3

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

AI-suggested

This vulnerability is fixed in Envoy versions 1.35.13, 1.36.9, 1.37.5, and 1.38.3. Users should upgrade to one of these versions or later to remediate the issue. No other official remediation or temporary fixes are indicated. Patch status is not explicitly stated in the input data, but the fixed versions are clearly identified, indicating an official fix is available.

Description

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.34.0 until 1.35.13, 1.36.9, 1.37.5, and 1.38.3, a vulnerability exists in Envoy's TCP StatsD sink (TcpStatsdSink), where the thread-local flusher buffer can be overflowed by exceptionally long statistic names (e.g., >16KiB). During formatting, TcpStatsdSink reserves a single contiguous memory slice of 16KiB (FLUSH_SLICE_SIZE_BYTES). If formatting a single metric exceeds the remaining capacity, the flusher initiates a buffer rotation but incorrectly continues to allocate another fixed 16KiB slice. If an attacker can trigger a statistic name longer than 16KiB—for example, by sending an HTTP or gRPC request with an extremely long request path (:path) that is recorded by the grpc_stats filter configured with stats_for_all_methods: true—the flusher will attempt to copy the metric name using memcpy operations beyond the allocated heap buffer boundaries. This leads to a heap write overflow, which can cause immediate denial-of-service (process crash) or potential remote code execution (RCE). This vulnerability is fixed in 1.35.13, 1.36.9, 1.37.5, and 1.38.3.

References

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