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CVE-2026-0819

Stack buffer overflow in PKCS7 SignedData encoding with custom signed attributes PUBLISHED

Description (CNA)

A 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.

Affected (CNA)

Vendor / productVersions
wolfSSL / wolfSSLaffected 5.5.0 before 5.9.0

CWE

CWE-121, CWE-787

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.