Out-of-bounds Write Affecting wolfssl package, versions <5.9.1-r0


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.02% (7th percentile)

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  • Snyk IDSNYK-ALPINE323-WOLFSSL-17037493
  • published29 May 2026
  • disclosed19 Mar 2026

Introduced: 19 Mar 2026

CVE-2026-0819  (opens in a new tab)
CWE-787  (opens in a new tab)

How to fix?

Upgrade Alpine:3.23 wolfssl to version 5.9.1-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream wolfssl package and not the wolfssl package as distributed by Alpine. See How to fix? for Alpine:3.23 relevant fixed versions and status.

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 Base Scores

version 3.1