Security Resilience

CVE-2026-35460

XSS in Papra ≤ 26.4.0

Public PoCXSS
Published
07 April 2026
Modified
24 April 2026
Patch / advisory
View advisory
CVSS Score v3.1 4.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
EPSS Score 0.0023 14th percentile
Risk Priority 35 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). EPSS scores by FIRST (EPSS SIG), generated by Empirical Security. Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-35460 is a medium-severity Cross-site Scripting (CWE-79) vulnerability in Papra Papra. Its CVSS base score is 4.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Browser Session Hijacking (T1185); ranked at the 14th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

Papra is a minimalistic document management and archiving platform. Prior to 26.4.0, transactional email templates in Papra interpolate user.name directly into HTML without escaping or sanitization. An attacker who registers with a display name containing HTML tags will have those…

more

tags injected into the verification and password reset email bodies. Since emails are sent from the legitimate domain (e.g: auth@mail.papra.app), this enables convincing phishing attacks that appear to originate from official Papra notifications. This vulnerability is fixed in 26.4.0.

CWE(s)
CWE-79CWE-80

Related Threats

MITRE ATT&CK Enterprise Techniques

T1059.007 JavaScript Execution
Adversaries may abuse various implementations of JavaScript for execution.
attack.mitre.org →
T1185 Browser Session Hijacking Collection
Adversaries may take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify user-behaviors, and intercept information as part of various browser session hijacking techniques.
attack.mitre.org →
T1189 Drive-by Compromise Initial Access
Adversaries may gain access to a system through a user visiting a website over the normal course of browsing.
attack.mitre.org →
T1539 Steal Web Session Cookie Credential Access
An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1204.001 Malicious Link Execution
An adversary may rely upon a user clicking a malicious link in order to gain execution.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-21612Shared CWE-79, CWE-80
CVE-2023-23735Shared CWE-79, CWE-80
CVE-2025-22402Shared CWE-79, CWE-80
CVE-2024-23817Shared CWE-79, CWE-80
CVE-2022-36097Shared CWE-79, CWE-80
CVE-2024-8680Shared CWE-79, CWE-80
CVE-2024-32464Shared CWE-79, CWE-80
CVE-2022-36094Shared CWE-79, CWE-80
CVE-2025-62172Shared CWE-79, CWE-80
CVE-2025-59854Shared CWE-79, CWE-80

Affected Assets

papra
papra
≤ 26.4.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.1.2
  • V1.3.2
  • V1.2.1
  • V1.3.1

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover missing or incorrect input neutralization through targeted web-application tests.

SI-10 Information Input Validation good match

Input validation directly enforces neutralization of untrusted data before it reaches web output generation.

SI-15 Information Output Filtering good match

Output filtering can catch or sanitize unneutralized script content before it is served to users.

SA-8 Security and Privacy Engineering Principles partial match

Secure engineering principles include mandatory output encoding and neutralization of HTML metacharacters to stop injection at the source.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
blocks

Secure SDLC practices directly target introduction of XSS via coding standards/testing (mostly), yet the single broad outcome leaves many specific neutralization vectors unaddressed (partial).

PR.PS-02 partial match
blocks

Patching and EOL replacement can remediate known XSS instances in libraries or frameworks (partial) but do nothing to enforce input neutralization in application code (none).

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Secure-coding testing and automated code-analysis tools are applied to detect improper neutralization of script-related content during web-page generation.

A.8.28 Secure coding partial match
prevents

Secure-coding standards, SAST scans and removal of insecure code samples together eliminate the failure to neutralize script content that produces cross-site scripting flaws.

References