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.
Published: 2026-10-26
Score: 6.9 Medium
EPSS: n/a
KEV: No
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History

Mon, 26 Oct 2026 20:00:00 +0000

Type Values Removed Values Added
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.
Title erlang-jose RSA JWK parsing attempts to factor an attacker-controlled modulus, enabling CPU-exhaustion denial of service
First Time appeared Potatosalad
Potatosalad jose
Weaknesses CWE-407
CPEs cpe:2.3:a:potatosalad:jose:*:*:*:*:*:*:*:*
Vendors & Products Potatosalad
Potatosalad jose
References
Metrics cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}


Subscriptions

Potatosalad Jose
cve-icon MITRE

Status: PUBLISHED

Assigner: EEF

Published:

Updated: 2026-10-26T19:53:45.204Z

Reserved: 2026-07-22T13:58:26.233Z

Link: CVE-2026-65631

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-26T20:17:58.997

Modified: 2026-10-26T20:17:58.997

Link: CVE-2026-65631

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses