CVE-2021-25786

Exp

An issue was discovered in QPDF version 10.0.4, allows remote attackers to execute arbitrary code via crafted .pdf file to Pl_ASCII85Decoder::write parameter in libqpdf.

Published: 2023-08-11 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-25786 is rated Exploit Available (54.9/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.30%). 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-2021-25786

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

Exploit prediction scoring system (EPSS) score for CVE-2021-25786

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 2025-11-21 0.12% 0.30% +0.18%
2 2025-11-18 0.30% 0.12% -0.18%
3 2025-03-30 — 0.30% —

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-25786

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L 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:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 1.8 3.4 [email protected]

Weakness enumeration for CVE-2021-25786

OS Trackers for CVE-2021-25786

vendor priority summary link
debian not yet assigned CVE-2021-25786 not yet assigned priority: Debian including 1 source packages (qpdf), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-25786
redhat medium — https://access.redhat.com/security/cve/CVE-2021-25786
suse high CVE-2021-25786 severity important: SUSE including 6 source package names (libqpdf18, libqpdf21, libqpdf26, libqpdf28, qpdf, qpdf-devel), 92 product×package rows across 33 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 7.1, … (33 product lines)): Known Not Affected 92. https://www.suse.com/security/cve/CVE-2021-25786/
ubuntu medium CVE-2021-25786 medium priority: Ubuntu including 1 source packages (qpdf), 8 status rows across 8 suites (bionic, focal, jammy, lunar, mantic, trusty, upstream, xenial): released 4, not-affected 3, ignored 1. https://ubuntu.com/security/CVE-2021-25786

Affected software / configurations for CVE-2021-25786

Vendor Product Version Raw CPE
qpdf_project qpdf 10.0.4 cpe:2.3:a:qpdf_project:qpdf:10.0.4:*:*:*:*:*:*:*

References for CVE-2021-25786

URL Tags
https://github.com/qpdf/qpdf/issues/492 Exploit Issue Tracking Patch
https://lists.debian.org/debian-lts-announce/2023/08/msg00037.html Mailing List Third Party Advisory
cvelogic Threat Intelligence