6.5

CVE-2026-1355: github enterprise_server Missing Authorization

CVSS: 6.5v3.1MediumAnalyzed
Published 18-02-2026Last modified 20-02-2026
Open JSON

Vulnerability summary

CVE-2026-1355 is a medium (CVSS 6.5) Missing Authorization vulnerability in github enterprise_server. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 38.3% of scored vulnerabilities.

Overall risk
26/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.46%
0%100%
Low · +0.05 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 18-02-2026
    PublishedVulnerability first disclosed.
  2. 20-02-2026
    Last modifiedVulnerability information updated.

Description

A Missing Authorization vulnerability was identified in GitHub Enterprise Server that allowed an attacker to upload unauthorized content to another user’s repository migration export due to a missing authorization check in the repository migration upload endpoint. By supplying the migration identifier, an attacker could overwrite or replace a victim’s migration archive, potentially causing victims to download attacker-controlled repository data during migration restores or automated imports. An attacker would require authentication to the victim's GitHub Enterprise Server instance. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.20 and was fixed in versions 3.19.2, 3.18.5, 3.17.11, 3.16.14, 3.15.18, 3.14.23. This vulnerability was reported via the GitHub Bug Bounty program.

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

0.46%

Chance of exploitation in the next 30 days

Percentile

38%

Versus all other CVEs

30-day change

+0.05 pp

From 0.40% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.46%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Github1 product
  • enterprise_server≥ 3.19.0, ≤ 3.19.1 | ≥ 3.18.0, ≤ 3.18.4 | ≥ 3.17.0, ≤ 3.17.10 | ≥ 3.16.0, ≤ 3.16.13 | ≥ 3.15.0, ≤ 3.15.17 | ≥ 3.14.0, ≤ 3.14.22 | < 3.14.23 | ≥ 3.15.0, < 3.15.18 | ≥ 3.16.0, < 3.16.14 | ≥ 3.17.0, < 3.17.11 | ≥ 3.18.0, < 3.18.5 | ≥ 3.19.0, < 3.19.2

1 vendor · 1 product

References

6 links