CVE-2026-26309

Summary

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 Software

VendorProductVersion RangeStatus
envoyproxyenvoy>= 1.37.0, < 1.37.1affected
envoyproxyenvoy>= 1.36.0, < 1.36.5affected
envoyproxyenvoy>= 1.35.0, < 1.35.9affected
envoyproxyenvoy< 1.34.13affected

Weaknesses

  • CWE-193: CWE-193: Off-by-one Error

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

References