Moderate severityNVD Advisory· Published Mar 10, 2026· Updated Mar 10, 2026
Envoy has an off-by-one write in JsonEscaper::escapeString()
CVE-2026-26309
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.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
github.com/envoyproxy/envoyGo | >= 1.36.0, <= 1.36.4 | — |
github.com/envoyproxy/envoyGo | >= 1.35.0, <= 1.35.8 | — |
github.com/envoyproxy/envoyGo | <= 1.34.12 | — |
Affected products
1- Range: >= 1.37.0, < 1.37.1
Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
3- github.com/advisories/GHSA-56cj-wgg3-x943ghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-26309ghsaADVISORY
- github.com/envoyproxy/envoy/security/advisories/GHSA-56cj-wgg3-x943ghsax_refsource_CONFIRMWEB
News mentions
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