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OpenAdvisories
Medium · 6.9 CVE-2026-3849 EUVD-2026-13231GHSA-267h-vrw9-53p3

Buffer Overflow in HPKE via Oversized ECH Config

Published Mar 19, 2026 · Updated Mar 25, 2026 · Assigned by wolfSSL

Description

Stack Buffer Overflow in wc_HpkeLabeledExtract via Oversized ECH Config. A vulnerability existed in wolfSSL 5.8.4 ECH (Encrypted Client Hello) support, where a maliciously crafted ECH config could cause a stack buffer overflow on the client side, leading to potential remote execution and client program crash. This could be exploited by a malicious TLS server supporting ECH. Note that ECH is off by default, and is only enabled with enable-ech.

Affected products

VendorProductAffectedFixed
wolfSSL wolfSSL — —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 13 wolfssl No fix yet —
Debian 12 wolfssl No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 wolfssl No fix yet —
Ubuntu 26.04 LTS wolfssl No fix yet —
Ubuntu 25.10 wolfssl No fix yet —
Ubuntu 24.04 LTS wolfssl No fix yet —
Ubuntu 22.04 LTS wolfssl No fix yet —
Show 3 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 20.04 LTS wolfssl No fix yet —
Ubuntu 18.04 LTS wolfssl No fix yet —
Ubuntu 16.04 LTS wolfssl No fix yet —
ReleasePackageFixed inAdvisory
Alpine v3.24 wolfssl 5.9.0-r0 —
Alpine v3.23 wolfssl 5.9.1-r0 —

References