CVE-2026-26309
Envoy has an off-by-one write in JsonEscaper::escapeString()
MEDIUM 5.3
At a glance
- Source
- NVD
- EPSS
- EPSS 0.39 % · percentile 33 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Analyzed
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.
Weaknesses (CWE)
- CWE-193 — Off-by-one Error
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L | GitHub_M |
| CVSS 3.1 | MEDIUM 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L | NVD · security-advisories@github.com (Secondary) |
| CVSS 3.1 | MEDIUM 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L | NVD · nvd@nist.gov (Primary) |
Advisories
- GHSA-56cj-wgg3-x943 — Envoy affected by off-by-one write in JsonEscaper::escapeString()
European references
- ENISA EUVD · EUVD-2026-10800
- GCVE · GCVE-0-2026-26309
Affected configurations (NVD CPE)
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*< 1.34.13cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*≥ 1.35.0 < 1.35.8cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*≥ 1.36.0 < 1.36.5cpe:2.3:a:envoyproxy:envoy:1.37.0:*:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| envoyproxy · envoy | affected >= 1.37.0, < 1.37.1 ; affected >= 1.36.0, < 1.36.5 ; affected >= 1.35.0, < 1.35.9 ; affected < 1.34.13 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |