Vulnerability · Published Sep 8, 2026 · Assigned by GitHub_M
CVE-2026-53938OpenIDC/cjose has a heap buffer overflow in AES Key Wrap decryption (A128KW/A192KW/A256KW)
High 8.2
In plain English
A high-severity heap buffer overflow in cjose from OpenIDC. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
OpenIDC/cjose is a C library implementing the Javascript Object Signing and Encryption (JOSE). Prior to version 0.6.2.5, cjose's JWE decryption path for the AES Key Wrap key-management algorithms (`alg` = `A128KW`, `A192KW`, `A256KW`) does not validate the length of the attacker-supplied `encrypted_key` (JWE Encrypted Key) before unwrapping it into a fixed-size, heap-allocated Content Encryption Key (CEK) buffer. A remote, unauthenticated attacker who can submit a crafted JWE to an application that decrypts it with an AES-KW symmetric key can trigger an out-of-bounds heap write, corrupting the heap. This leads at minimum to a crash (denial of service) and, depending on the heap layout and allocator, may be leverageable for further memory-corruption impact. `cjose_jwe_import()` / `cjose_jwe_decrypt()` are pre-authentication entry points: they parse and process fully attacker-controlled input. Upgrade to cjose 0.6.2.5 to receive a patch. If upgrading is not immediately possible, reject the AES Key Wrap algorithms (`A128KW`/`A192KW`/`A256KW`) for untrusted JWEs at the application layer.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | cjose | 0.6.2.2-7.el10_2.1 | ALSA-2026:79122 |
| AlmaLinux:8 | cjose | 0.6.1-5.module_el8.10.0+4297+63ae3533 | ALSA-2026:77369 |
| AlmaLinux:9 | cjose | 0.6.1-17.el9_8.1 | ALSA-2026:90812 |
| AlmaLinux:10 | cjose-devel | 0.6.2.2-7.el10_2.1 | ALSA-2026:79122 |
| AlmaLinux:8 | cjose-devel | 0.6.1-5.module_el8.10.0+4297+63ae3533 | ALSA-2026:77369 |
| AlmaLinux:9 | cjose-devel | 0.6.1-17.el9_8.1 | ALSA-2026:90812 |
| AlmaLinux:8 | mod_auth_openidc | 2.4.9.4-9.module_el8.10.0+4297+63ae3533 | ALSA-2026:77369 |
| Debian:12 | cjose | no fix listed | DEBIAN-CVE-2026-53938 |
| Debian:13 | cjose | 0.6.2.3-1+deb13u1 | DEBIAN-CVE-2026-53938 |
| Debian:14 | cjose | 0.6.2.7-1 | DEBIAN-CVE-2026-53938 |
| Rocky Linux:10 | cjose | 0:0.6.2.2-7.el10_2.1 | RLSA-2026:79122 |
| Rocky Linux:8 | cjose | 0:0.6.1-5.module+el8.10.0+40373+8a3f15d2 | RLSA-2026:77369 |
| Rocky Linux:9 | cjose | 0:0.6.1-17.el9_8.1 | RLSA-2026:90812 |
| Rocky Linux:8 | mod_auth_openidc | 0:2.4.9.4-9.module+el8.10.0+40373+8a3f15d2 | RLSA-2026:77369 |
| Ubuntu:22.04:LTS | cjose | no fix listed | UBUNTU-CVE-2026-53938 |
| Ubuntu:24.04:LTS | cjose | no fix listed | UBUNTU-CVE-2026-53938 |
| Ubuntu:26.04:LTS | cjose | no fix listed | UBUNTU-CVE-2026-53938 |
| Ubuntu:26.10 | cjose | no fix listed | UBUNTU-CVE-2026-53938 |
Affected products (as reported)
Weakness: CWE-122, CWE-787 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H