CVE-2026-5500 json
Improper Validation of AES-GCM Authentication Tag Length in PKCS#7 Envelope Allows Authentication Bypass
published 2026-04-10 7 mo ago modified 2026-07-25 3 mo ago also EUVD-2026-21293 , GHSA-m77r-vqw2-hffx , JLSEC-2026-729
- cvss
- 5.9
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 42%
- public exploits
- 0
- none known
Summary
wolfSSL's wc_PKCS7_DecodeAuthEnvelopedData() does not properly sanitize the AES-GCM authentication tag length received and has no lower bounds check. A man-in-the-middle can therefore truncate the mac field from 16 bytes to 1 byte, reducing the tag check from 2⁻¹²⁸ to 2⁻⁸.
Patch / fix
- julia wolfSSL_jll 5.9.2+0
- wolfssl Alpine 3.24, Alpine 3.23 5.9.1-r0
alpine advisories ALPINE-CVE-2026-5500
Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0
- github.com/wolfSSL/wolfssl#10102 pull request
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 6 mo ago
Exploit prediction
0.49% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.7 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N |
| CNA | 4.0 | 8.7 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N |
| OSV | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| julia | wolfSSL_jll | <5.9.2+0 |
5.9.2+0 |
Affected products
- wolfSSL wolfSSL
Classification
- Weakness
-
- CWE-20 Improper Input Validation
References
-
github.com
/wolfSSL/wolfssl/pull/10102
issue-tracking, web
-
github.com
/advisories/GHSA-m77r-vqw2-hffx
web
-
nvd.nist.gov
/vuln/detail/CVE-2026-5500
web
Sources
- CVE List CVE-2026-5500
- NVD CVE-2026-5500
- OSV JLSEC-2026-729
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.