Is CVE-2026-26309 actively exploited?

No active exploitation of CVE-2026-26309 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-26309 be exploited remotely?

Yes. CVE-2026-26309 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-26309?

CVE-2026-26309 has a CVSS score of 5.3 (MEDIUM).

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MEDIUM

CVE-2026-26309

CWE-193Published: March 10, 2026· Updated: Mar 11, 2026

5.3

CVSS v3.1

EPSS:0.00%probability of exploitation in 30 daysPercentile:0.1th

Official 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.

NVD Source

Technical Analysis

CVE-2026-26309 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.