CVE-2026-5477
CVE-2026-5477 · Prefix-substitution forgery via integer overflow in wolfCrypt CMAC
This page contains facts from public vulnerability sources. Check the original advisory before updating.
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.
CVSS 8.2 · High · EPSS 0.4%
- Published
- Updated
Stack: system
Affected products and versions
wolfssl
- Versions
- ≥ 0, ≤ 5.9.0: Affected (semver)
No fix published
wolfssl Debian:12
- Versions
- 5.5.4-2
- 5.5.4-2+deb12u1
- 5.5.4-2+deb12u2
- 5.5.4-2+deb12u3
- 5.5.4-2.1
- 5.6.4-1
- 5.6.4-2
- 5.6.6-1
- 5.6.6-1.1
- 5.6.6-1.2
- 5.6.6-1.3
- 5.6.6-1.3~exp1
- 5.7.0-0.1
- 5.7.0-0.2
- 5.7.0-0.3
- 5.7.2-0.1
- 5.7.2-0.2
- 5.7.2-0.3
- 5.7.2-0.4
- 5.8.2-1
- 5.8.2-1.1
- 5.8.2-1.2
- 5.8.4-1
- 5.9.0-0.1
- 5.9.0-0.2
- 5.9.1-0.1
- 5.9.2-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Debian:13
- Versions
- 5.7.2-0.1
- 5.7.2-0.1+deb13u1
- 5.7.2-0.1+deb13u2
- 5.7.2-0.2
- 5.7.2-0.3
- 5.7.2-0.4
- 5.8.2-1
- 5.8.2-1.1
- 5.8.2-1.2
- 5.8.4-1
- 5.9.0-0.1
- 5.9.0-0.2
- 5.9.1-0.1
- 5.9.2-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:16.04:LTS
- Versions
- 3.4.8+dfsg-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:18.04:LTS
- Versions
- 3.10.2+dfsg-2
- 3.12.0+dfsg-1
- 3.12.2+dfsg-1
- 3.13.0+dfsg-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:20.04:LTS
- Versions
- 4.1.0+dfsg-2
- 4.2.0+dfsg-1
- 4.2.0+dfsg-2
- 4.2.0+dfsg-3
- 4.3.0+dfsg-2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:22.04:LTS
- Versions
- 4.6.0-3
- 5.0.0-1
- 5.1.1-1
- 5.2.0-1
- 5.2.0-2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:24.04:LTS
- Versions
- 5.5.4-2
- 5.5.4-2.1
- 5.6.4-2
- 5.6.6-1.2
- 5.6.6-1.3
- 5.6.6-1.3build1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:25.10
- Versions
- 5.7.2-0.1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:26.10
- Versions
- 5.9.1-0.1
- 5.9.2-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
wolfssl Ubuntu:26.04:LTS
- Versions
- 5.7.2-0.1
- 5.8.2-1.2
- 5.8.4-1
- 5.9.1-0.1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published