CVE-2021-3508

Exp

A flaw was found in PDFResurrect in version 0.22b. There is an infinite loop in get_xref_linear_skipped() in pdf.c via a crafted PDF file.

Published: 2021-04-28 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-3508 is rated Exploit Available (55.1/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.76%). 1 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-2021-3508

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

Exploit prediction scoring system (EPSS) score for CVE-2021-3508

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 0.34% 0.76% +0.42%
2 2025-11-21 0.17% 0.34% +0.17%
3 2025-11-18 — 0.17% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-3508

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
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.
 1.8 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2021-3508

OS Trackers for CVE-2021-3508

vendor priority summary link
debian unimportant CVE-2021-3508 unimportant priority: Debian including 1 source packages (pdfresurrect), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2021-3508
ubuntu medium CVE-2021-3508 medium priority: Ubuntu including 1 source packages (pdfresurrect), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 8, released 5, needed 2, needs-triage 1. https://ubuntu.com/security/CVE-2021-3508

Affected software / configurations for CVE-2021-3508

Vendor Product Version Raw CPE
pdfresurrect_project pdfresurrect 0.22b cpe:2.3:a:pdfresurrect_project:pdfresurrect:0.22b:*:*:*:*:*:*:*

References for CVE-2021-3508

URL Tags
https://bugzilla.redhat.com/show_bug.cgi?id=1951198 Issue Tracking Patch Third Party Advisory
https://github.com/enferex/pdfresurrect/issues/17 Exploit Patch Third Party Advisory
cvelogic Threat Intelligence