CVE catalog

CVE-2026-5477

Severity: High · CVSS 8.2
Published: Apr 10, 2026, 6:16:05 AM UTC
Source: [NVD] · [CVE record]
EPSS: 0.38% · Oct 25, 2026

An integer overflow existed in the wolfCrypt CMAC implementation, that could be exploited to forge CMAC tags. The function wc_CmacUpdate used the guard `if (cmac->totalSz != 0)` to skip XOR-chaining on the first block (where digest is all-zeros and the XOR is a no-op). However, totalSz is word32 and wraps to zero after 2^28 block flushes (4 GiB), causing the guard to erroneously discard the live CBC-MAC chain state. Any two messages sharing a common suffix beyond the 4 GiB mark then produce identical CMAC tags, enabling a zero-work prefix-substitution forgery. The fix removes the guard, making the XOR unconditional; the no-op property on the first block is preserved because digest is zero-initialized by wc_InitCmac_ex.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	wolfssl	sid	`5.9.2-1.2`	fixed
Debian	wolfssl	trixie	`5.7.2-0.1+deb13u2`	vulnerable
Debian	wolfssl	bookworm	`5.5.4-2+deb12u2`	vulnerable
Debian	wolfssl	bookworm-security	`5.5.4-2+deb12u3`	vulnerable
Cpe	wolfssl	Not reported	Not reported	vulnerable
Cpe	wolfssl	Not reported	Not reported	unknown

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	wolfssl	source	sid	`5.9.1-0.1`	not yet assigned	Not reported	[1133835]
Debian	wolfssl	source	trixie	`(unfixed)`	not yet assigned	Not reported	[1133835]
Debian	wolfssl	source	bookworm	`(unfixed)`	not yet assigned	Not reported	[1133835]

[Debian bug #1133835]

Notes

[trixie] wolfssl: Minor issue [bookworm] wolfssl: Minor issue

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[libwolfssl35]Affected
Source package: [wolfssl]
Details (4)
- 5.5.4-2+deb12u2 · amd64 · bookworm
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u2 · arm64 · bookworm
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · amd64 · bookworm-security
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · arm64 · bookworm-security
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
[libwolfssl-dev]Affected
Source package: [wolfssl]
Details (4)
- 5.5.4-2+deb12u2 · amd64 · bookworm
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u2 · arm64 · bookworm
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · amd64 · bookworm-security
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · arm64 · bookworm-security
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12

[Debian 13 (Trixie)]

[libwolfssl42t64]Affected
Source package: [wolfssl]
Details (2)
- 5.7.2-0.1+deb13u1 · amd64 · trixie
  Affected
  nvd · wolfssl · debian · 13
- 5.7.2-0.1+deb13u1 · arm64 · trixie
  Affected
  nvd · wolfssl · debian · 13
[libwolfssl-dev]Affected
Source package: [wolfssl]
Details (2)
- 5.7.2-0.1+deb13u1 · amd64 · trixie
  Affected
  nvd · wolfssl · debian · 13
- 5.7.2-0.1+deb13u1 · arm64 · trixie
  Affected
  nvd · wolfssl · debian · 13

Observed: Oct 23, 2026, 10:34:23 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database]