CVE-2025-40907 | FCGI versions 0.44 through 0.82, for Perl, include a vulnerable version of the FastCGI fcgi2 (aka fcgi) library

Exp

FCGI versions 0.44 through 0.82, for Perl, include a vulnerable version of the FastCGI fcgi2 (aka fcgi) library. The included FastCGI library is affected by CVE-2025-23016, causing an integer overflow (and resultant heap-based buffer overflow) via crafted nameLen or valueLen values in data to the IPC socket. This occurs in ReadParams in fcgiapp.c.

Published: 2025-05-16 Last update: 2025-09-29 Assigner: 9b29abf9-4ab0-4765-b253-1875cd9b441e Source: 9b29abf9-4ab0-4765-b253-1875cd9b441e
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-40907 is rated High Exploit Risk (62.2/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.76%). 3 public exploit reference(s) are indexed (Exploit-DB). 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-2025-40907

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

Exploit prediction scoring system (EPSS) score for CVE-2025-40907

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 2026-03-12 0.27% 0.76% +0.49%
2 2026-03-02 0.16% 0.27% +0.10%
3 2025-12-10 — 0.16% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-40907

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L 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:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 1.4 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2025-40907

OS Trackers for CVE-2025-40907

vendor priority summary link
alpine — CVE-2025-40907: 1 source package rows (perl-fcgi); 7 state rows across 6 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, 3.23-main, edge-main); fixed 0, open 7. https://security.alpinelinux.org/vuln/CVE-2025-40907
debian not yet assigned CVE-2025-40907 not yet assigned priority: Debian including 1 source packages (libfcgi-perl), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2025-40907
redhat high — https://access.redhat.com/security/cve/CVE-2025-40907
suse medium CVE-2025-40907 severity moderate: SUSE including 3 source package names (perl-FCGI-0.74-8.el7_9.1, perl-FCGI-0.78-12.module+el8.10.0+23147+df114ff4, perl-FCGI-0.79-8.1.el9_6), 3 product×package rows across 3 product lines (SUSE Liberty Linux 7 LTSS, SUSE Liberty Linux 8, SUSE Liberty Linux 9): Fixed 3. https://www.suse.com/security/cve/CVE-2025-40907/
ubuntu medium CVE-2025-40907 medium priority: Ubuntu including 1 source packages (libfcgi-perl), 8 status rows across 8 suites (bionic, focal, jammy, noble, oracular, plucky, upstream, xenial): not-affected 4, released 4. https://ubuntu.com/security/CVE-2025-40907

Affected software / configurations for CVE-2025-40907

Vendor Product Version Raw CPE
fastcgi fcgi >= 0.44, <= 0.82 cpe:2.3:a:fastcgi:fcgi:*:*:*:*:*:perl:*:*

References for CVE-2025-40907

cvelogic Threat Intelligence