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CVE Record

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

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().

CriticalCVSS 9.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

A Linux TCP flaw can use memory after it has been freed during a failed request-socket migration retry. This can destabilize affected systems and may threaten confidentiality, integrity, and availability. The supplied CVSS score is 9.8, but the sources do not establish practical exploitation or observed attacks.

Executive priority

Treat remediation as urgent for affected, network-facing Linux systems because the supplied severity is critical. First resolve the ambiguous version mapping through vendor advisories, then patch confirmed exposures promptly. There is no supplied evidence of active exploitation, so avoid describing this as an ongoing attack campaign.

Technical view

CVE-2024-53206 is a CWE-416 use-after-free in reqsk_timer_handler(). During request-socket migration, a failed retry can cause reqsk_put() to receive req instead of the original oreq, potentially freeing and later using nreq incorrectly. The kernel fix changes the reference passed to reqsk_put().

Likely exposure

Exposure is limited to Linux kernels containing the vulnerable TCP request-socket logic. The bundle's version status is internally difficult to interpret, listing some later releases as affected while identifying earlier releases and commits as unaffected. Confirm exposure using distribution package versions and fix backport status, not upstream version numbers alone.

Exploitation context

The supplied CVSS vector describes unauthenticated network reachability with low complexity and no user interaction. However, KEV is false, and the supplied sources provide no evidence of active exploitation or a public working exploit. Real-world exploitability and impact beyond the described use-after-free remain unconfirmed.

Researcher notes

The vulnerable path requires request-socket migration followed by a failed retry, such as a timeout. The correction passes oreq rather than req to reqsk_put(). The source bundle does not document reliable triggering conditions, demonstrated code execution, exploit availability, or attack telemetry. Distribution backports may make simple kernel-version comparisons unreliable.

Mitigation direction

  • Apply a vendor-supported kernel update containing the linked upstream fix.
  • Review Linux distribution advisories for package-specific fixed versions and backports.
  • Prioritize externally reachable systems processing untrusted TCP traffic.
  • Use vendor guidance for temporary mitigations if immediate kernel replacement is unavailable.
  • Reboot where required to ensure the corrected kernel is active.

Validation and detection

  • Record each system's running kernel and distribution package release.
  • Compare package versions against the applicable vendor security advisory.
  • Confirm the installed kernel incorporates the relevant upstream fix commit.
  • Verify systems booted into the updated kernel after maintenance.
  • Monitor kernel logs for crashes or memory-safety warnings involving request sockets.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-416: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2024-53206 mapping review

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Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.8 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
3Timeline events
2ADP providers
8Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: total

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
9.8CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Linux
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

9.8Critical
CVSS 3.1 vector shape for CVE-2024-53206Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux8459d61fbf24967839a70235165673148c7c7f17, 5071beb59ee416e8ab456ac8647a4dabcda823b1, 997ae8da14f1639ce6fb66a063dab54031cd61b3, 51e34db64f4e43c7b055ccf881b7f3e0c31bb26d, e8c526f2bdf1845bedaf6a478816a3d06fa78b8f, e8c526f2bdf1845bedaf6a478816a3d06fa78b8f, 106e457953315e476b3642ef24be25ed862aaba3, c964bf65f80a14288d767023a1b300b30f5b9cd0, 5.15.170, 6.1.115, 6.6.59, 6.11.6, 5.4.293, 5.10.237unaffected
LinuxLinux6.12, 0, 5.15.174, 6.1.120, 6.6.64, 6.11.11, 6.12.2, 6.13affected
Weakness

CWE details

CWE-416

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-416 · source CWE mapping

Use After Free

Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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