CVE-2026-74483

UNRATEDCVSS · not yet scoredTrending — 5 sources updated this week
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EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • No CVSS published and no exploitation signals yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS v2: —Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In the Linux kernel, the following vulnerability has been resolved:

binfmt_misc: don't leak the user namespace when the mount fails

bm_get_tree() takes a reference to the user namespace and hands it to get_tree_keyed() as the sget key. sget_fc() moves that reference into sb->s_fs_info and clears fc->s_fs_info, so from that point on the superblock owns it and bm_free() doesn't see it anymore.

The superblock drops it in ->put_super(). But generic_shutdown_super() only calls ->put_super() from inside the if (sb->s_root) branch, so nothing releases it when bm_fill_super() fails:

  • The kzalloc_obj() failure leaves s_root NULL and the whole branch is
skipped.
  • A simple_fill_super() failure in the file loop leaves s_root set, but
s_op still points at simple_super_operations, which has no ->put_super(). bm_fill_super() installs s_ops only once simple_fill_super() returned success, and installing it earlier wouldn't help either because simple_fill_super() overwrites s_op.

Either way vfs_get_super() calls deactivate_locked_super() and the reference is gone for good. binfmt_misc mounts are available in a user namespace and both the inode and the dentry cache are SLAB_ACCOUNT, so an unprivileged caller under a tight memory cgroup can fail simple_fill_super() on demand and leak one user namespace per attempt.

Drop the reference in ->kill_sb() instead, which runs unconditionally, the same way nfsd and rpc_pipefs release their keyed s_fs_info.

That also stops ->put_super() from clearing s_fs_info while the superblock is still on @fs_supers. generic_shutdown_super() leaves it there on purpose so that sget_fc() keeps finding it until kill_sb() has run, but a NULL s_fs_info makes test_keyed_super() miss it, so a concurrent mount for the same user namespace skips the grab_super() wait and creates a second superblock for a namespace that is still being torn down.

CVSS v3
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EchelonGraph score
Not yet assessedNo source has published severity data for this CVE yet — no CVSS score from NVD or a CNA, no GitHub advisory, and it is not in CISA KEV. This is not a rating of zero; we cannot assess it yet.
EG Score
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EG Risk
—
EPSS PROB
0%
EPSS %ILE
5%
KEV
Not listed

Published

August 15, 2026

Last Modified

August 17, 2026

References (2)

Vendor Advisories for CVE-2026-74483(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 16× in last 7d / 16× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-20 22:56 UTCEPSS rescore
  2. 2026-08-20 03:38 UTCGHSA enrichment
  3. 2026-08-19 17:04 UTCEPSS rescore
  4. 2026-08-18 13:49 UTCEPSS rescore
  5. 2026-08-18 13:49 UTCEPSS rescore
  6. 2026-08-17 13:47 UTCEPSS rescore
  7. 2026-08-17 06:24 UTCGHSA enrichment
  8. 2026-08-17 06:22 UTCNVD update
  9. 2026-08-17 05:25 UTCEG score recompute
  10. 2026-08-17 05:25 UTCGHSA enrichment
  11. 2026-08-17 05:24 UTCMITRE cvelistV5
  12. 2026-08-16 14:56 UTCEPSS rescore
  13. 2026-08-16 14:56 UTCEPSS rescore
  14. 2026-08-15 13:27 UTCNVD update
  15. 2026-08-15 12:40 UTCEG score recompute
  16. 2026-08-15 12:37 UTCMITRE cvelistV5first tracked

Frequently asked(4)

What is CVE-2026-74483?
CVE-2026-74483 is a publicly disclosed vulnerability published on August 15, 2026. In the Linux kernel, the following vulnerability has been resolved: binfmt_misc: don't leak the user namespace when the mount fails bmgettree() takes a reference to the user namespace and hands it to gettreekeyed() as the sget key. sget_fc() moves that reference into sb->sfsinfo and clears…
When was CVE-2026-74483 disclosed?
CVE-2026-74483 was first published in the National Vulnerability Database on August 15, 2026, with the most recent update on August 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-74483 actively exploited?
CVE-2026-74483 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 94.8% of all scored CVEs.
How do I remediate CVE-2026-74483?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-74483, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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