NVD / CVE Program· CNA Linux

CVE-2026-53175: inet: frags: fix use-after-free caused by the fqdir_pre_exit() flush

Noroxi assessment

Priority: Monitor (action score 39/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.31% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
Fixed version: Linux Linux 010c3313a4d178dc2d3ce958d2e5cb055e2864c1, 0e823ca0e7391630784ae7dd0981b7ad170a93d9, 32594b09854970d7ba83eb2dc8c69a2edd158c8e.

Low priority for now. Upgrade to Linux Linux 010c3313a4d178dc2d3ce958d2e5cb055e2864c1, 0e823ca0e7391630784ae7dd0981b7ad170a93d9, 32594b09854970d7ba83eb2dc8c69a2edd158c8e or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: inet: frags: fix use-after-free caused by the fqdir_pre_exit() flush On netns teardown, fqdir_pre_exit() walks the fqdir rhashtable and flushes every fragment queue that is not yet complete using inet_frag_queue_flush(). That helper frees all the skbs queued on the fragment queue but does not set INET_FRAG_COMPLETE, and leaves q->fragments_tail and q->last_run_head pointing at the freed skbs. The queue itself stays in the rhashtable. fqdir_pre_exit() first lowers high_thresh to 0 to stop new queue lookups, but it cannot stop a fragment that already obtained the queue through inet_frag_find() earlier and stalled just before taking the queue lock. Once that fragment resumes after the flush and takes the queue lock, it passes the INET_FRAG_COMPLETE check and then dereferences the freed fragments_tail. inet_frag_queue_insert() reads FRAG_CB() and ->len of that pointer and, on the append path, writes ->next_frag, causing a slab use-after-free. IPv6, nf_conntrack_reasm6 and 6lowpan reassembly share the same flush path and are affected as well. Reset rb_fragments, fragments_tail and last_run_head in inet_frag_queue_flush() so a flushed queue no longer points at the freed skbs. A fragment that resumes after the flush and takes the queue lock then finds an empty queue and starts a new run instead of dereferencing the freed fragments_tail. ip_frag_reinit() already performed this reset after its own flush, so drop the now duplicate code there.

CriticalCVSS 9.8 · v3.1—No exploit Fix available

BDU:2026-14019

Published: Jun 25, 2026
Updated: Sep 1, 2026
EPSS: 0.3% · 24th percentile
CWE: CWE-416

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 39 / 40 · 9.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.3%

CNA vs NVD score

NVD: —
CNA · Linux: 9.8; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

linux linux kernel6.18.3 and later · before 6.18.36
linux linux kernel6.19.1 and later · before 7.0.13
linux linux kernel6.12.93
linux linux kernel6.19
linux linux kernel7.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

Linux Linux
- 6.19affected
- 22ee4010866da81aeee08e1ea3fddbe418feb212 and later · before 0e823ca0e7391630784ae7dd0981b7ad170a93d9affected · git
- 543555954b1ee8d1903a7020324efb41b0c97428 and later · before c22599cc90e1cd5f8129c8670bd68a02ff7177b4affected · git
- c70df25214ac9b32b53e18e6ae3b8f073ffa6903 and later · before 89b909e9704587bfecc1aab1d37e98faee03b9f9affected · git
- 006a5035b495dec008805df249f92c22c89c3d2e and later · before 010c3313a4d178dc2d3ce958d2e5cb055e2864c1affected · git
- 006a5035b495dec008805df249f92c22c89c3d2e and later · before 32594b09854970d7ba83eb2dc8c69a2edd158c8eaffected · git
- 6.12.93 and later · before 6.12.94affected · semver
- 6.18.3 and later · before 6.18.36affected · semver
- before 6.19not affected · semver
- 6.12.94 and later · up to and including 6.12.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:14	linux	before 7.0.13-1	7.0.13-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
90Now
CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
89Now
CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
85Now

Published before and after this one in the same product

← EarlierCVE-2026-53173Jun 25, 2026 · accel/ethosu: fix OOB write in ethosu_gem_cmdstream_copy_and_validate()
31Monitor
← EarlierCVE-2026-53174Jun 25, 2026 · ovl: keep err zero after successful ovl_cache_get()
31Monitor
Later →CVE-2026-53190Jun 25, 2026 · drm/virtio: fix dma_fence refcount leak on error in virtio_gpu_dma_fence_wait()
22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Linux Linux	010c3313a4d178dc2d3ce958d2e5cb055e2864c1	Vendor (CNA)
Linux Linux	0e823ca0e7391630784ae7dd0981b7ad170a93d9	Vendor (CNA)
Linux Linux	32594b09854970d7ba83eb2dc8c69a2edd158c8e	Vendor (CNA)
Linux Linux	6.12.94	Vendor (CNA)
Linux Linux	6.18.36	Vendor (CNA)
Linux Linux	89b909e9704587bfecc1aab1d37e98faee03b9f9	Vendor (CNA)
Linux Linux	c22599cc90e1cd5f8129c8670bd68a02ff7177b4	Vendor (CNA)
debian:linux	7.0.13-1 · Debian:14	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

Fix✗ → ✓Sep 28, 2026, 10:10 PM UTC

For records you follow, these changes also arrive as notifications. →

References

git.kernel.org/stable/c/010c3313a4d178dc2d3ce958d2e5cb055e2864c1

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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