CVE-2026-0819
CVE-2026-0819 is a high-severity vulnerability in Wolfssl with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.
Key facts
- Severity: High (CVSS 3.x base score 7.1)
- CVSS v4: 2.2
- EPSS exploit prediction: 0% (1st percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-13131
- Weakness: CWE-787
- Affected product: Wolfssl
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-0819?
- 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.
- How severe is CVE-2026-0819?
- CVE-2026-0819 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
- Is CVE-2026-0819 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-0819?
- CVE-2026-0819 affects Wolfssl. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-0819?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-0819 have an EU (EUVD) identifier?
- Yes. CVE-2026-0819 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13131.
- When was CVE-2026-0819 published?
- CVE-2026-0819 was published on 2026-03-19 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*
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