NVD / CVE Program· CNA Linux

CVE-2024-53206: tcp: Fix use-after-free of nreq in reqsk_timer_handler().

Noroxi assessment

Priority: Monitor (action score 31/100)

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: 0.63% (FIRST EPSS); higher than 50.5% of all records.
Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: Linux Linux 2dcc86fefe09ac853158afd96b60d544af115dc5, 5.11, 5.15.174; cbl2 kernel 5.15.173.1-2 on CBL Mariner 2.0 5.15.176.3-1; cbl2 kernel 5.15.173.1-2 on CBL-Mariner 2.0 5.15.176.3-1.
Severity is disputed: the assigning authority (CNA) scores it 9.8, NVD 7.8.

Low priority for now. Upgrade to Linux Linux 2dcc86fefe09ac853158afd96b60d544af115dc5, 5.11, 5.15.174; cbl2 kernel 5.15.173.1-2 on CBL Mariner 2.0 5.15.176.3-1; cbl2 kernel 5.15.173.1-2 on CBL-Mariner 2.0 5.15.176.3-1 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: tcp: Fix use-after-free of nreq in reqsk_timer_handler(). The cited commit replaced inet_csk_reqsk_queue_drop_and_put() with __inet_csk_reqsk_queue_drop() and reqsk_put() in reqsk_timer_handler(). Then, oreq should be passed to reqsk_put() instead of req; otherwise use-after-free of nreq could happen when reqsk is migrated but the retry attempt failed (e.g. due to timeout). Let's pass oreq to reqsk_put().

HighCVSS 7.8 · v3.1—No exploit Fix available

Memory safety

Published: Dec 27, 2024
Updated: Aug 5, 2026
EPSS: 0.6% · 50th percentile
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.6%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 7.8
CNA · Linux: 9.8; 2.0 point gap

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

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

Get told when this record changes

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?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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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.

ProductVersion

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 kernel5.15.170 and later · before 5.15.174
linux linux kernel6.1.115 and later · before 6.1.120
linux linux kernel6.6.59 and later · before 6.6.64
linux linux kernel6.11.6 and later · before 6.11.11
linux linux kernel6.12 and later · before 6.12.2

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
- 106e457953315e476b3642ef24be25ed862aaba3, c964bf65f80a14288d767023a1b300b30f5b9cd0, 6.12affected
- 8459d61fbf24967839a70235165673148c7c7f17 and later · before 2dcc86fefe09ac853158afd96b60d544af115dc5affected · git
- 5071beb59ee416e8ab456ac8647a4dabcda823b1 and later · before 9a3c1ad93e6fba67b3a637cfa95a57a6685e4908affected · git
- 997ae8da14f1639ce6fb66a063dab54031cd61b3 and later · before 65ed89cad1f57034c256b016e89e8c0a4ec7c65baffected · git
- 51e34db64f4e43c7b055ccf881b7f3e0c31bb26d and later · before d0eb14cb8c08b00c36a3d5dc57a6f428b301f721affected · git
- e8c526f2bdf1845bedaf6a478816a3d06fa78b8f and later · before 6d845028609a4af0ad66f499ee0bd5789122b067affected · git
- e8c526f2bdf1845bedaf6a478816a3d06fa78b8f and later · before c31e72d021db2714df03df6c42855a1db592716caffected · git
- 5.15.170 and later · before 5.15.174affected · semver
- 6.1.115 and later · before 6.1.120affected · semver
- 6.6.59 and later · before 6.6.64affected · semver

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
Debian:12	linux	before 6.1.123-1	6.1.123-1
Debian:13	linux	before 6.12.3-1	6.12.3-1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	kernel-64kb	before 5.14.21-150400.24.147.1	5.14.21-150400.24.147.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	kernel-docs	before 5.14.21-150400.24.147.1	5.14.21-150400.24.147.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	kernel-obs-build	before 5.14.21-150400.24.147.1	5.14.21-150400.24.147.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	kernel-source	before 5.14.21-150400.24.147.1	5.14.21-150400.24.147.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	kernel-syms	before 5.14.21-150400.24.147.1	5.14.21-150400.24.147.1
SUSE:Linux Enterprise Live Patching 15 SP4	kernel-livepatch-SLE15-SP4_Update_35	before 1-150400.9.3.1	1-150400.9.3.1
SUSE:Linux Enterprise Micro 5.3	kernel-default	before 5.14.21-150400.24.147.1	5.14.21-150400.24.147.1
SUSE:Linux Enterprise Micro 5.3	kernel-default-base	before 5.14.21-150400.24.147.1.150400.24.72.1	5.14.21-150400.24.147.1.150400.24.72.1
SUSE:Linux Enterprise Server 15 SP4-LTSS	kernel-zfcpdump	before 5.14.21-150400.24.147.1	5.14.21-150400.24.147.1

Same product

linux: all records

Other highest-scoring records for the same primary product.

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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
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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-2024-53204Dec 27, 2024 · phy: realtek: usb: fix NULL deref in rtk_usb3phy_probe
22Monitor
← EarlierCVE-2024-53205Dec 27, 2024 · phy: realtek: usb: fix NULL deref in rtk_usb2phy_probe
22Monitor
Later →CVE-2024-53207Dec 27, 2024 · Bluetooth: MGMT: Fix possible deadlocks
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	2dcc86fefe09ac853158afd96b60d544af115dc5	Vendor (CNA)
Linux Linux	5.11	Vendor (CNA)
Linux Linux	5.15.174	Vendor (CNA)
Linux Linux	5.5	Vendor (CNA)
Linux Linux	6.1.120	Vendor (CNA)
Linux Linux	6.11.11	Vendor (CNA)
Linux Linux	6.6.64	Vendor (CNA)
Linux Linux	65ed89cad1f57034c256b016e89e8c0a4ec7c65b	Vendor (CNA)
Linux Linux	6d845028609a4af0ad66f499ee0bd5789122b067	Vendor (CNA)
Linux Linux	9a3c1ad93e6fba67b3a637cfa95a57a6685e4908	Vendor (CNA)
Linux Linux	c31e72d021db2714df03df6c42855a1db592716c	Vendor (CNA)
Linux Linux	d0eb14cb8c08b00c36a3d5dc57a6f428b301f721	Vendor (CNA)
cbl2 kernel 5.15.173.1-2 on CBL Mariner 2.0	5.15.176.3-1 · CBL-Mariner Releases	Microsoft (MSRC)
cbl2 kernel 5.15.173.1-2 on CBL-Mariner 2.0	5.15.176.3-1 · CBL-Mariner Releases	Microsoft (MSRC)
cbl2 kernel 5.15.176.3-1 on CBL Mariner 2.0	5.15.176.3-1 · CBL-Mariner Releases	Microsoft (MSRC)
debian:linux	6.1.123-1 · Debian:12	Package registry (OSV)
suse:kernel-64kb	5.14.21-150400.24.147.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	Package registry (OSV)
suse:kernel-default	5.14.21-150400.24.147.1 · SUSE:Linux Enterprise Micro 5.3	Package registry (OSV)
suse:kernel-default-base	5.14.21-150400.24.147.1.150400.24.72.1 · SUSE:Linux Enterprise Micro 5.3	Package registry (OSV)
suse:kernel-docs	5.14.21-150400.24.147.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	Package registry (OSV)
suse:kernel-livepatch-SLE15-SP4_Update_35	1-150400.9.3.1 · SUSE:Linux Enterprise Live Patching 15 SP4	Package registry (OSV)
suse:kernel-obs-build	5.14.21-150400.24.147.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	Package registry (OSV)
suse:kernel-source	5.14.21-150400.24.147.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	Package registry (OSV)
suse:kernel-syms	5.14.21-150400.24.147.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	Package registry (OSV)
suse:kernel-zfcpdump	5.14.21-150400.24.147.1 · SUSE:Linux Enterprise Server 15 SP4-LTSS	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

Someone with local access to the system can trigger it.
A low-privileged account is enough.
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: Local
Attack complexity: Low
Privileges required: Low
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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-primary

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, 10:09 PM UTC

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

References

git.kernel.org/stable/c/2dcc86fefe09ac853158afd96b60d544af115dc5

Show all references (6 more)

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

All records