7.5

CVE-2026-15788: WCOW cache mount source selector resolves NTFS junctions outside of cache root

Analyzed
Published 20-07-2026Last modified 21-07-2026

Vulnerability summary

CVE-2026-15788 is a high (CVSS 7.5) vulnerability in moby buildkit. EPSS estimates a 0.41% chance of exploitation in the next 30 days, higher than 35.4% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.6, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (NVD)
EPSS score
0.41%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 4
RHSA-2026:43122RHSA-2026:44152RHSA-2026:46988RHSA-2026:51065

Timeline

  1. 20-07-2026
    PublishedVulnerability first disclosed.
  2. 21-07-2026
    Last modifiedVulnerability information updated.

Description

BuildKit's cache mount source= selector on Windows Container on Windows (WCOW) workers does not detect NTFS directory junctions placed inside the cache root. A build authored by an untrusted user on a WCOW-configured BuildKit daemon can read arbitrary host files reachable to the BuildKit daemon process.

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

0.41%

Chance of exploitation in the next 30 days

Percentile

35%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.41% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.

Moby1 product
Mobyproject1 product

2 vendors · 2 products

References

1 links