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Linux KernelOperating system · Linux

CVE-2026-53151

CRITICAL · 9.8 CVSS v3.1 Published 2026-06-25
Fix available
A fix is available. Upgrade to 6.6.144 / 6.12.95 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix the ACK parser to extract the SACK table for parsing Fix modification of the received skbuff in rxrpc_input_soft_acks() and a potential incorrect access of the buffer in a fragmented UDP packet (the packet would probably have to be deliberately pre-generated as fragmented) when AF_RXRPC tries to extract the contents of the SACK table by copying out the contents of the SACK table into a buffer before attempting to parse AF_RXRPC assumes that it can just call skb_condense() and then validly access the SACK table from skb->data and that it will be a flat buffer - but skb_condense() can silently fail to do anything under some circumstances. Note that whilst rxrpc_input_soft_acks() should be able to parse extended ACKs, the rest of AF_RXRPC doesn't currently support that. Further, there's then no need to call skb_condense() in rxrpc_input_ack(), so don't.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Linux kernel's AF_RXRPC protocol implementation has a vulnerability in rxrpc_input_soft_acks() where it attempts to extract SACK table contents by accessing skb->data after calling skb_condense(), but skb_condense() can silently fail to consolidate fragmented or non-linear socket buffers. This can lead to incorrect buffer access, potentially allowing memory corruption or denial of service when handling specially crafted fragmented UDP packets.

MitigationApply the Linux kernel patch that removes the unsafe assumption about skb_condense() success and implements proper SACK table extraction. Update affected systems to the patched kernel version.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 6.2, < 6.6.144>= 6.7, < 6.12.95>= 6.13, < 6.18.36>= 6.19, < 7.0.13= 7.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check the installed kernel version
    Run `uname -r` or `cat /proc/version` to identify the running kernel version
    Affected if The kernel version falls within one of these ranges: >= 6.2 and < 6.6.144; >= 6.7 and < 6.12.95; >= 6.13 and < 6.18.36; >= 6.19 and < 6.19 and < 7.0.13; or equals 7.1
  2. Verify if AF_RXRPC kernel module is loaded
    Run `lsmod | grep rxrpc` to check if the rxrpc module is currently loaded in memory
    Affected if The rxrpc module is loaded and the kernel version is in the affected range above
  3. Check for AF_RXRPC support in kernel configuration
    Check the kernel config file (typically /boot/config-$(uname -r) or /proc/config.gz) for CONFIG_AF_RXRPC=y or CONFIG_AF_RXRPC=m
    Affected if AF_RXRPC support is compiled into the kernel (y) or as a loadable module (m) and the kernel version is in the affected range
  4. Detect active AF_RXRPC sockets
    Run `ss -x | grep rxrpc` or check /proc/net/af_rxr* to see if any AF_RXRPC sockets are currently in use
    Affected if Any AF_RXRPC sockets are established while the kernel version is in the affected range

The environment is affected if the running kernel version is within the affected ranges AND AF_RXRPC protocol support is enabled (either as a loaded module or compiled in) and potentially in use.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.6.144 / 6.12.95 / 6.18.36 or later
Fixed in 6.6.1446.12.956.18.36
Vendor patch git.kernel.org →
Interim mitigation

Apply the Linux kernel patch that removes the unsafe assumption about skb_condense() success and implements proper SACK table extraction. Update affected systems to the patched kernel version.

Recommended fix High confidence

Upgrade to kernel 6.6.144 (if on 6.2-6.6.x), 6.12.95 (if on 6.7-6.12.x), 6.18.36 (if on 6.13-6.18.x), or 7.0.13 (if on 6.19-7.0.x)

  1. Identify the currently running Linux kernel version using `uname -r`
  2. Determine which version range your current kernel falls into from the affected versions: >= 6.2 and < 6.6.144, >= 6.7 and < 6.12.95, >= 6.13 and < 6.18.36, or >= 6.19 and < 7.0.13
  3. Upgrade the Linux kernel to the first fixed version in your version branch: if on 6.2-6.6.x upgrade to 6.6.144+, if on 6.7-6.12.x upgrade to 6.12.95+, if on 6.13-6.18.x upgrade to 6.18.36+, or if on 6.19-7.0.x upgrade to 7.0.13+
  4. Reboot the system to load the new kernel
  5. Verify the kernel was upgraded successfully using `uname -r`
Caveat Kernel upgrades may require rebuild of out-of-tree kernel modules; ensure compatible drivers/modules are available before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation3.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
20.0 hours of engineering $3,480
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-53151 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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