CVE-2026-40505 | MuPDF < 1.27 mutool ANSI Injection via Metadata

MuPDF before 1.27 contains an ANSI injection vulnerability in mutool that allows attackers to inject arbitrary ANSI escape sequences through crafted PDF metadata fields. Attackers can embed malicious ANSI escape codes in PDF metadata that are passed unsanitized to terminal output when running mutool info, enabling them to manipulate terminal display for social engineering attacks such as presenting fake prompts or spoofed commands.

Published: 2026-04-16 Last update: 2026-05-26 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-40505 is rated Low Risk (19.8/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.01%). Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

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-2026-40505

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 2026-04-16 — 0.01% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-40505

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.8 4.0 MEDIUM
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Click to expand
Attack vector (AV:L)
Attacker needs local access on the target system.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:N)
No privileges are required.
User interaction (UI:P)
A user has to participate (for example click/open/approve).
Vulnerable system confidentiality impact (VC:N)
No confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:L)
Limited integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:N)
No availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:X)
Not defined: no reliable threat intelligence; scoring assumes the worst case (equivalent to Attacked).
Confidentiality requirement (CR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Integrity requirement (IR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Availability requirement (AR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Modified attack vector (MAV:X)
Not defined: scoring uses the Base Attack Vector (AV).
Modified attack complexity (MAC:X)
Not defined: scoring uses the Base Attack Complexity (AC).
Modified attack requirements (MAT:X)
Not defined: scoring uses the Base Attack Requirements (AT).
Modified privileges required (MPR:X)
Not defined: scoring uses the Base Privileges Required (PR).
Modified user interaction (MUI:X)
Not defined: scoring uses the Base User Interaction (UI).
Modified vulnerable system confidentiality impact (MVC:X)
Not defined: scoring uses the Base VC metric.
Modified vulnerable system integrity impact (MVI:X)
Not defined: scoring uses the Base VI metric.
Modified vulnerable system availability impact (MVA:X)
Not defined: scoring uses the Base VA metric.
Modified subsequent system confidentiality impact (MSC:X)
Not defined: scoring uses the Base SC metric.
Modified subsequent system integrity impact (MSI:X)
Not defined: scoring uses the Base SI metric.
Modified subsequent system availability impact (MSA:X)
Not defined: scoring uses the Base SA metric.
Safety (supplemental) (S:X)
Not evaluated.
Automatable (supplemental) (AU:X)
Not evaluated.
Recovery (supplemental) (R:X)
Not evaluated.
Value density (supplemental) (V:X)
Not evaluated.
Vulnerability response effort (supplemental) (RE:X)
Not evaluated.
Provider urgency (supplemental) (U:X)
Not evaluated.
 — — [email protected]
3.3 3.1 LOW
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N 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:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 1.8 1.4 [email protected]

Weakness enumeration for CVE-2026-40505

GitHub Security Advisory for CVE-2026-40505

GHSA-hj44-m5xv-x75q · Severity: medium — MuPDF mutool does not sanitize PDF metadata fields before writing them to terminal output,...

OS Trackers for CVE-2026-40505

vendor priority summary link
debian not yet assigned CVE-2026-40505 not yet assigned priority: Debian including 1 source packages (mupdf), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 3, resolved 2. https://security-tracker.debian.org/tracker/CVE-2026-40505
suse medium — https://www.suse.com/security/cve/CVE-2026-40505/
ubuntu medium CVE-2026-40505 medium priority: Ubuntu including 1 source packages (mupdf), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, resolute, upstream, xenial): needs-triage 8. https://ubuntu.com/security/CVE-2026-40505

Affected software / configurations for CVE-2026-40505

Vendor Product Version Raw CPE
artifex mupdf < 1.27.0 cpe:2.3:a:artifex:mupdf:*:*:*:*:*:*:*:*

References for CVE-2026-40505

cvelogic Threat Intelligence