Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Wolfssl | Wolfssl | >= 5.5.0, < 5.9.0 |
Related Weaknesses (CWE)
References
- https://github.com/wolfSSL/wolfssl/pull/9630Issue TrackingPatch
FAQ
What is CVE-2026-0819?
CVE-2026-0819 is a vulnerability with a CVSS score of 7.1 (HIGH). 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 incorre...
How severe is CVE-2026-0819?
CVE-2026-0819 has been rated HIGH with a CVSS base score of 7.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-0819?
Check the references section above for vendor advisories and patch information. Affected products include: Wolfssl Wolfssl.