CVE-2024-26142 | Rails possible ReDoS vulnerability in Accept header parsing in Action Dispatch

Rails is a web-application framework. Starting in version 7.1.0, there is a possible ReDoS vulnerability in the Accept header parsing routines of Action Dispatch. This vulnerability is patched in 7.1.3.1. Ruby 3.2 has mitigations for this problem, so Rails applications using Ruby 3.2 or newer are unaffected.

Published: 2024-02-27 Last update: 2025-02-14 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2024-26142 is rated Moderate Risk (61.5/100): CVSS High severity, with medium exploitation likelihood (EPSS 3.54%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2024-26142

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-17 2.64% 3.54% +0.90%
2 2026-03-04 1.70% 2.64% +0.94%
3 2026-03-01 — 1.70% —

Full EPSS history (38 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2024-26142

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2024-26142

GitHub Security Advisory for CVE-2024-26142

GHSA-jjhx-jhvp-74wq · Severity: low · Ecosystem: rubygems — Rails has possible ReDoS vulnerability in Accept header parsing in Action Dispatch

OS Trackers for CVE-2024-26142

vendor priority summary link
debian unimportant CVE-2024-26142 unimportant priority: Debian including 1 source packages (rails), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2024-26142
redhat medium — https://access.redhat.com/security/cve/CVE-2024-26142
suse high — https://www.suse.com/security/cve/CVE-2024-26142/
ubuntu medium CVE-2024-26142 medium priority: Ubuntu including 7 source packages (rails, rails-4.0, …), 77 status rows across 11 suites (bionic, focal, jammy, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 54, needs-triage 12, ignored 10, not-affected 1. https://ubuntu.com/security/CVE-2024-26142

Affected software / configurations for CVE-2024-26142

Vendor Product Version Raw CPE
rubyonrails rails >= 7.1.0, < 7.1.3.1 cpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*

References for CVE-2024-26142

cvelogic Threat Intelligence