CVE-2024-2757 | PHP mb_encode_mimeheader runs endlessly for some inputs

Exp

In PHP 8.3.* before 8.3.5, function mb_encode_mimeheader() runs endlessly for some inputs that contain long strings of non-space characters followed by a space. This could lead to a potential DoS attack if a hostile user sends data to an application that uses this function.

Published: 2024-04-29 Last update: 2025-11-04 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2024-2757 is rated High Exploit Risk (73.3/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.92%). 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +1.28% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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

Public exploit references (Exploit-DB) for CVE-2024-2757

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2024-2757

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 2026-06-15 0.64% 1.92% +1.28%
2 2025-11-21 3.30% 0.64% -2.66%
3 2025-11-18 — 3.30% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2024-2757

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]

Weakness enumeration for CVE-2024-2757

OS Trackers for CVE-2024-2757

vendor priority summary link
alpine — CVE-2024-2757: 1 source package rows (php83); 5 state rows across 5 repos (3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 5, open 0. https://security.alpinelinux.org/vuln/CVE-2024-2757
debian unimportant CVE-2024-2757 unimportant priority: Debian including 2 source packages (php7.4, php8.2), 2 status rows across 2 suites (bookworm, bullseye): resolved 2. https://security-tracker.debian.org/tracker/CVE-2024-2757
gentoo high CVE-2024-2757: 1 GLSA(s) (202408-32), 1 atom(s) (dev-lang/php); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2024-2757
redhat medium — https://access.redhat.com/security/cve/CVE-2024-2757
suse high CVE-2024-2757 severity important: SUSE including 367 source package names (apache2-mod_php5, apache2-mod_php7, …), 1361 product×package rows across 24 product lines (SUSE Enterprise Storage 7.1, SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS, … (24 product lines)): Known Not Affected 1260, Fixed 101. https://www.suse.com/security/cve/CVE-2024-2757/
ubuntu medium CVE-2024-2757 medium priority: Ubuntu including 7 source packages (php5, php7.0, …), 44 status rows across 8 suites (bionic, focal, jammy, mantic, noble, trusty, upstream, xenial): DNE 30, not-affected 12, released 2. https://ubuntu.com/security/CVE-2024-2757

Affected software / configurations for CVE-2024-2757

Vendor Product Version Raw CPE
php php >= 8.3.0, < 8.3.5 cpe:2.3:a:php:php:*:*:*:*:*:*:*:*

References for CVE-2024-2757

cvelogic Threat Intelligence