CVE-2026-26309Disclosure(envoyproxy / envoy)

LOWCVSS 5.3 · MEDIUM

Signal is active with 3 mentions in latest observed window

Immediate actions

Patch envoyproxy envoy systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD 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, an off-by-one write in Envoy::JsonEscaper::escapeString() can corrupt std::string null-termination, causing undefined behavior and potentially leading to crashes or out-of-bounds reads when the resulting string is later treated as a C-string. This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.

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0.5/ 10 priority

Sources & remediation

Exploit / PoC references

https://github.com/envoyproxy/envoy/security/advisories/GHSA-56cj-wgg3-x943

Weakness type (CWE)

CWE-193

Priority

LOW

Exploitation

NONE

PoC

YES

Patch

AVAILABLE

Momentum

NONE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

envoy

Threat summary

Patch or workaround signal is available
3 mentions across 1 observed day

What's happening

Patch or workaround mentioned in 2 signals
Technical details provided in 3 signals
Disclosure: 2 classified signals
3 total mentions across 1 day

Affected systems

Vendors

envoyproxy

Products

envoy

1 version affected across 1 product

Deep dive

Activity timeline3 mentions / 1d

Signal classification2 categories

Disclosure

266.7%

Patch

133.3%

Referenced assets3 URLs

By indicator

Full discourse3 posts

Infoflowcloud@infoflowcloud213d
Disclosure
🚨*CVE* CVE-2026-26309 Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, an off-by-one write in Envoy::JsonEscaper::escapeString() can cor… https://www.cve.org/CVERecord?id=CVE-2026-26309 ----- Traducción: CVE-2026-26309 Env… http://infoflow.cloud`
Post summary
The post announces CVE-2026-26309, describing an off‑by‑one write vulnerability in Envoy's JSON escaper that impacts several release versions.
0000015
57 followersView on X
CVE@CVEnew213d
Disclosure
CVE-2026-26309 Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, an off-by-one write in Envoy::JsonEscaper::escapeString() can cor… https://www.cve.org/CVERecord?id=CVE-2026-26309
Post summary
The post discloses a CVE describing an off‑by‑one write in Envoy's JsonEscaper affecting specific versions, with a link to the CVE record and implied patch versions.
00000191
56.7K followersView on X
Volerion@VolerionSec213d
Patch
🚨 CVE-2026-26309: Remote off-by-one bug in Envoy’s JSON string escaper can corrupt memory and crash your proxy. Patch to 1.37.1 or the latest stable release now! Full advisory ➡️ https://volerion.com/vulnerabilities/CVE-2026-26309 #Envoy #infosec #DevOps
Post summary
The tweet announces CVE‑2026‑26309 in Envoy, explains an off‑by‑one memory corruption bug that can crash the proxy, and urges users to patch to 1.37.1 or later.
0000046
50 followersView on X

CPE platform detail2 entries

Part:

Vendor:

Product:

Version:

Target SW:

Target HW:

2 of 2 entries

Part	Vendor	Product	Version	Target SW	Target HW
App	envoyproxy	envoy	-	-	-
App	envoyproxy	envoy	1.37.0	-	-

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