CVE WatchOct 7, 2026

CVE-2025-52881

runc is a CLI tool for spawning and running containers according to the OCI specification. In versions 1.2.7, 1.3.2 and 1.4.0-rc.2, an attac

CVSS

7.5

High

EPSS

0.6%

p46

KEV

—

Exploit Today

0-100

Published: Nov 6, 2025 · Last modified: Oct 7, 2026 · CWE-61 · CWE-363

EPSS · 30d

0.6%EPSS · 30 days0.6%

2026-09-212026-10-19

Technical description

runc is a CLI tool for spawning and running containers according to the OCI specification. In versions 1.2.7, 1.3.2 and 1.4.0-rc.2, an attacker can trick runc into misdirecting writes to /proc to other procfs files through the use of a racing container with shared mounts (we have also verified this attack is possible to exploit using a standard Dockerfile with docker buildx build as that also permits triggering parallel execution of containers with custom shared mounts configured). This redirect could be through symbolic links in a tmpfs or theoretically other methods such as regular bind-mounts. While similar, the mitigation applied for the related CVE, CVE-2019-19921, was fairly limited and effectively only caused runc to verify that when LSM labels are written they are actually procfs files. This issue is fixed in versions 1.2.8, 1.3.3, and 1.4.0-rc.3.

Official references

Related CVEs

CVECVSSEPSSKEVRExploitTitleMod.

CVE-2026-1129407.1 HIG

—

———filelock is a platform-independent file lock for Python. From 3.20.4 until 4.2.1, ReadWriteLock let SQLite reopen the database and side files by name; on POSIX systems an attacker with rename access in a non-sticky parent can swap those names to cause overwrite or unlink operations, while a writable adjacent hot journal is additionally required for attacker-chosen content overwrites. This issue is fixed in version 4.2.1.4h CVE-2026-1129145.3 MED

—

———filelock is a platform-independent file lock for Python. From 4.1.0 until 4.2.1, SoftFileLock can restore a stale marker by name after moving it aside, allowing another local user with rename access in a non-sticky lock directory to swap in a symbolic link and, on a runtime that follows the link and a same-filesystem target, make the lock user hard-link one of its files into the lock directory. This issue is fixed in version 4.2.1.4h CVE-2026-1027405.8 MED

0.8%

——0The AsyncHttpClient library allows Java applications to execute HTTP requests and asynchronously process HTTP responses. From 2.0.0 until 2.16.1 and 3.0.12, PropertiesBasedResumableProcessor stores resumable download state at the predictable shared path $java.io.tmpdir/ahc/ResumableAsyncHandler.properties with default permissions and link-following file operations. A local user who can read the shared store can see download URLs, including embedded user information or query tokens. A local user who can write within or pre-create the affected shared store directory can plant a symbolic link that the client follows when saving state, truncating and overwriting a target file writable by the client process. The filesystem path is used when ResumableAsyncHandler decorates another AsyncHandler, while the no-argument constructors use a no-op processor and are unaffected. This issue is fixed in versions 2.16.1 and 3.0.12.4d CVE-2026-50612—

40.7%

——12An unix symbolic link (symlink) following vulnerability has been reported to affect QuMagie. If a remote attacker gains a user account, they can then exploit the vulnerability to compromise the security of the system. We have already fixed the vulnerability in the following version: QuMagie 2.9.2 and later5d CVE-2026-41541—

44.4%

——13An unix symbolic link (symlink) following vulnerability has been reported to affect Qsync Central. If a remote attacker gains a user account, they can then exploit the vulnerability to compromise the security of the system. We have already fixed the vulnerability in the following version: Qsync Central 5.0.0.7 and later Qsync Central 5.1.0.3 and later Qsync Central 5.2.0.5 and later Qsync Central 5.3.0.2 and later5d CVE-2026-1089813.6 LOW

1.5%

——0ngx_cache_purge before 3.0.4 can allow file deletion via a symlink attack in certain situations where nginx and a served application (e.g., WordPress) run under the same user account. The attacker must be able to create a symlink inside the cache path. Version 3.0.4 fixes this for the case of a symlink created at an arbitrary earlier time, but does not resolve an applicable TOCTOU race condition. (The ngx_cache_purge module follows symlinks while walking the cache directory tree during purge operations. The module relies on nginx's ngx_walk_tree(), which relies on stat() and therefore follows symlinks.)4d