CVE-2026-53938: openidc cjose Heap-based Buffer Overflow
Vulnerability summary
CVE-2026-53938 is a high (CVSS 8.2) Heap-based Buffer Overflow vulnerability in openidc cjose. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 13.6% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 8 · Related 6Timeline
- 08-09-2026PublishedVulnerability first disclosed.
- 09-09-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
5 scores · 5 sources · 1 version- OSV · Red hatEcosystem advisory · calculated8.2HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
- OSV · UbuntuEcosystem advisory · calculated8.2HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
- OSV · DebianEcosystem advisory · calculated8.2HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
- NVDNIST8.2HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
EPSS trend
Probability
0.24%
Chance of exploitation in the next 30 days
Percentile
14%
Versus all other CVEs
30-day change
0.00 pp
From 0.24% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-122Heap-based Buffer OverflowA heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
- CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.
Affected systems
Redhat7 products
- cjose< 0:0.6.1-13.el9_2.1 | < 0:0.6.1-16.el9_4.1 | < 0:0.6.1-17.el9_6.1 | < 0:0.6.2.2-7.el10_0.1 | < 0:0.6.1-3.module+el8.8.0+24970+620d53ef.1 | < 0:0.6.1-3.module+el8.6.0+24971+334c209b.1 | < 0:0.6.1-3.module+el8.4.0+24972+63eee48e.1 | < 0:0.6.2.2-7.el10_2.1
- cjose-debuginfo< 0:0.6.1-13.el9_2.1 | < 0:0.6.1-16.el9_4.1 | < 0:0.6.1-17.el9_6.1 | < 0:0.6.2.2-7.el10_0.1 | < 0:0.6.1-3.module+el8.8.0+24970+620d53ef.1 | < 0:0.6.1-3.module+el8.6.0+24971+334c209b.1 | < 0:0.6.1-3.module+el8.4.0+24972+63eee48e.1 | < 0:0.6.2.2-7.el10_2.1
- cjose-debugsource< 0:0.6.1-13.el9_2.1 | < 0:0.6.1-16.el9_4.1 | < 0:0.6.1-17.el9_6.1 | < 0:0.6.2.2-7.el10_0.1 | < 0:0.6.1-3.module+el8.8.0+24970+620d53ef.1 | < 0:0.6.1-3.module+el8.6.0+24971+334c209b.1 | < 0:0.6.1-3.module+el8.4.0+24972+63eee48e.1 | < 0:0.6.2.2-7.el10_2.1
- cjose-devel< 0:0.6.1-17.el9_6.1 | < 0:0.6.2.2-7.el10_0.1 | < 0:0.6.1-3.module+el8.8.0+24970+620d53ef.1 | < 0:0.6.1-3.module+el8.6.0+24971+334c209b.1 | < 0:0.6.1-3.module+el8.4.0+24972+63eee48e.1 | < 0:0.6.2.2-7.el10_2.1
- mod_auth_openidc< 0:2.4.9.4-1.module+el8.8.0+24885+7d8e9f68.3 | < 0:2.4.9.4-1.module+el8.6.0+24867+df0294a5.3 | < 0:2.4.9.4-1.module+el8.4.0+24868+593d10ef.3
Debian1 product
- cjoseAll versions (No fix recorded) | < 0.6.2.3-1+deb13u1 | < 0.6.2.7-1
Openidc1 product
- cjose< 0.6.2.5
Ubuntu1 product
- cjoseAll versions (No fix recorded)
4 vendors · 10 products
