erlang-jose · Inefficient Algorithmic Complexity
Affects joseSource GCVE Database
Not known to be exploited · CVSS 6.9 Medium.
Data as of 28 Oct 2026, 22:28 UTC
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 26 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10josepkg:deb/ubuntu/jose?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSjosepkg:deb/ubuntu/jose?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSjosepkg:deb/ubuntu/jose?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSjosepkg:deb/ubuntu/jose?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 20.04 LTSjosepkg:deb/ubuntu/jose?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Ubuntu 18.04 LTSjosepkg:deb/ubuntu/jose?arch=source&distro=bionicOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
Inefficient Algorithmic Complexity in erlang-jose allows an unauthenticated remote attacker to cause a CPU-exhaustion denial of service by submitting a crafted RSA JSON Web Key. When an application parses an untrusted JWK through the public jose_jwk:from_binary/1 or jose_jwk:from_map/1 API (or the Elixir wrappers JOSE.JWK.from_binary/1 and JOSE.JWK.from_map/1), an RSA private key that supplies d, e, and n but omits all Chinese Remainder Theorem parameters (p, q, dp, dq, qi) is routed into convert_sfm_to_crt/1, which tries to recover the missing primes by factoring the modulus. The three integers are read straight from the base64url input and are never validated as a real RSA key. When the modulus cannot be split into two factors (for example, when it is itself prime), the search loop convert_sfm_to_crt_find_p/6 performs a modular exponentiation over the attacker-sized modulus on every iteration and never succeeds. A single request of a few hundred bytes forces close to one CPU-second of work before an internal one-second watchdog kills the worker, and a larger modulus raises the cost further. By flooding such requests an attacker can saturate every scheduler and deny service, without credentials, a valid RSA key, or any special configuration. This issue affects jose: from 1.7.7 before 1.11.13.
References
- ubuntu.com/security/CVE-2026-65631 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-65631 (opens in a new tab)
- cna.erlef.org/cves/cve-2026-65631.html (opens in a new tab)
- github.com (opens in a new tab)
- github.com/potatosalad/erlang-jose (opens in a new tab)
- github.com/potatosalad/erlang-jose/commit/bfd336c0062bff93e65d08c22361897e96afd956 (opens in a new tab)
- github.com/potatosalad/erlang-jose/commit/d19e1ba68d88c68d29aa942be2573a22dbafca1f (opens in a new tab)
- github.com/potatosalad/erlang-jose/security/advisories/ghsa-3m45-vrpj-xmrq (opens in a new tab)
- hex.pm/packages/jose (opens in a new tab)
- repo.hex.pm (opens in a new tab)
- github.com/cveproject/cvelistv5/tree/main/cves/2026/65xxx/cve-2026-65631.json (opens in a new tab)
- nvd.nist.gov/vuln/detail/cve-2026-65631 (opens in a new tab)
- osv.dev/vulnerability/eef-cve-2026-65631 (opens in a new tab)