Vulnerability Details 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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 4.9%
CVSS Severity
CVSS v3 Score 7.1
References
Products affected by CVE-2026-0819
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cpe:2.3:a:wolfssl:wolfssl:5.5.0
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cpe:2.3:a:wolfssl:wolfssl:5.5.1
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cpe:2.3:a:wolfssl:wolfssl:5.5.2
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cpe:2.3:a:wolfssl:wolfssl:5.5.3
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cpe:2.3:a:wolfssl:wolfssl:5.5.4
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cpe:2.3:a:wolfssl:wolfssl:5.6.0
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cpe:2.3:a:wolfssl:wolfssl:5.6.2
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cpe:2.3:a:wolfssl:wolfssl:5.6.3
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cpe:2.3:a:wolfssl:wolfssl:5.6.4
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cpe:2.3:a:wolfssl:wolfssl:5.6.6
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cpe:2.3:a:wolfssl:wolfssl:5.7.0
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cpe:2.3:a:wolfssl:wolfssl:5.7.2
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cpe:2.3:a:wolfssl:wolfssl:5.7.4
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cpe:2.3:a:wolfssl:wolfssl:5.7.6
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cpe:2.3:a:wolfssl:wolfssl:5.8.0
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cpe:2.3:a:wolfssl:wolfssl:5.8.2
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cpe:2.3:a:wolfssl:wolfssl:5.8.4