CVE-2026-0819

NameCVE-2026-0819
DescriptionA stack buffer overflow vulnerability exists in wolfSSL's PKCS7 SignedData encoding functionality. In wc_PKCS7_BuildSignedAttributes(), when adding custom signed attributes, the code passes an incorrect capacity value (esd->signedAttribsCount) to EncodeAttributes() instead of the remaining available space in the fixed-size signedAttribs[7] array. When an application sets pkcs7->signedAttribsSz to a value greater than MAX_SIGNED_ATTRIBS_SZ (default 7) minus the number of default attributes already added, EncodeAttributes() writes beyond the array bounds, causing stack memory corruption. In WOLFSSL_SMALL_STACK builds, this becomes heap corruption. Exploitation requires an application that allows untrusted input to control the signedAttribs array size when calling wc_PKCS7_EncodeSignedData() or related signing functions.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
wolfssl (PTS)bullseye4.6.0+p1-0+deb11u2vulnerable
bookworm5.5.4-2+deb12u2vulnerable
trixie5.7.2-0.1+deb13u1vulnerable
forky5.8.4-1vulnerable
sid5.9.0-0.1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
wolfsslsource(unstable)5.9.0-0.1

Notes

https://github.com/wolfSSL/wolfssl/pull/9630
Fixed by: https://github.com/wolfSSL/wolfssl/commit/9c7b58656541e8d31876d7ccd2cd38140b8ffb79 (v5.9.0-stable)

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