Cyber Resilience

CVE-2026-2995

XSS in Gitlab 15.4.0 – 18.8.7

Published
25 March 2026
Modified
26 March 2026
Patch / advisory
CVSS Score v3.1 7.7
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
EPSS Score 0.0019 9th percentile
Risk Priority 52 floored blend · peak EPSS

Summary

CVE-2026-2995 is a high-severity Basic XSS (CWE-80) vulnerability in Gitlab Gitlab. Its CVSS base score is 7.7 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Browser Session Hijacking (T1185); ranked at the 9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

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.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-2995 is a vulnerability in GitLab Enterprise Edition (EE) affecting all versions from 15.4 prior to 18.8.7, 18.9 prior to 18.9.3, and 18.10 prior to 18.10.1. The flaw arises from improper sanitization of HTML content, enabling an authenticated user to add email addresses to targeted user accounts. It is associated with CWE-79 (Cross-site Scripting) and CWE-80 (Improper Neutralization of Script-Related HTML Tags in a Web Page), and carries a CVSS v3.1 base score of 7.7 (AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N).

An authenticated attacker with low privileges (PR:L) could exploit this vulnerability over the network (AV:N), though it requires high attack complexity (AC:H) and user interaction (UI:R). Exploitation would allow the attacker to modify targeted user accounts by adding unauthorized email addresses, resulting in high impacts to confidentiality and integrity (C:H/I:H) within a changed scope (S:C), with no availability disruption (A:N).

GitLab has remediated the issue, with fixes included in versions 18.8.7, 18.9.3, and 18.10.1. Security practitioners should upgrade to these patched versions. Additional details are available in the GitLab patch release notes at https://about.gitlab.com/releases/2026/03/25/patch-release-gitlab-18-10-1-released/, the associated work item at https://gitlab.com/gitlab-org/gitlab/-/work_items/591065, and the HackerOne disclosure report at https://hackerone.com/reports/3564600.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

GitLab has remediated an issue in GitLab EE affecting all versions from 15.4 before 18.8.7, 18.9 before 18.9.3, and 18.10 before 18.10.1 that could have allowed an authenticated user to add email addresses to targeted user accounts due to improper…

more

sanitization of HTML content.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

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.
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.
T1659 Content Injection Initial Access
Adversaries may gain access and continuously communicate with victims by injecting malicious content into systems through online network traffic.
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.
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.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-5933Same product: Gitlab Gitlab
CVE-2023-2442Same product: Gitlab Gitlab
CVE-2023-2164Same product: Gitlab Gitlab
CVE-2023-1836Same product: Gitlab Gitlab
CVE-2022-1190Same product: Gitlab Gitlab
CVE-2023-2015Same product: Gitlab Gitlab
CVE-2020-13340Same product: Gitlab Gitlab
CVE-2022-1175Same product: Gitlab Gitlab
CVE-2023-6033Same product: Gitlab Gitlab
CVE-2022-2230Same product: Gitlab Gitlab

Affected Assets

gitlab
gitlab
18.10.0 · 15.4.0 — 18.8.7 · 18.9.0 — 18.9.3

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

Developer testing and evaluation can discover missing or incorrect neutralization of script tags through targeted XSS test cases.

Input validation explicitly requires checking and neutralizing untrusted web inputs containing script-related characters before they reach a downstream renderer.

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

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
prevents

Secure SDLC practices directly require output encoding and input validation that prevent basic XSS.

PR.PS-02 partial match
prevents

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.

finds

Security testing in development catches unneutralized script tags before release.

prevents

Knowledge exchange on emerging attack techniques and patches reduces the likelihood that cross-site scripting flaws remain unaddressed in deployed applications.

prevents

Operational indicators of compromise for web-application attacks can be incorporated into WAF or input-filtering rules, lowering the likelihood that unsanitized data reaches the browser.

prevents

Secure SDLC mandates input validation and output encoding that directly prevent basic XSS.

prevents

Application security requirements explicitly call for neutralization of script-related HTML tags.

prevents

Secure coding standards require proper escaping of <, >, & to block XSS.

References