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CVE Record

CVE-2023-53186: skbuff: Fix a race between coalescing and releasing SKBs

In the Linux kernel, the following vulnerability has been resolved: skbuff: Fix a race between coalescing and releasing SKBs Commit 1effe8ca4e34 ("skbuff: fix coalescing for page_pool fragment recycling") allowed coalescing to proceed with non page pool page and page pool page when @from is cloned, i.e. to->pp_recycle --> false from->pp_recycle --> true skb_cloned(from) --> true However, it actually requires skb_cloned(@from) to hold true until coalescing finishes in this situation. If the other cloned SKB is released while the merging is in process, from_shinfo->nr_frags will be set to 0 toward the end of the function, causing the increment of frag page _refcount to be unexpectedly skipped resulting in inconsistent reference counts. Later when SKB(@to) is released, it frees the page directly even though the page pool page is still in use, leading to use-after-free or double-free errors. So it should be prohibited. The double-free error message below prompted us to investigate: BUG: Bad page state in process swapper/1 pfn:0e0d1 page:00000000c6548b28 refcount:-1 mapcount:0 mapping:0000000000000000 index:0x2 pfn:0xe0d1 flags: 0xfffffc0000000(node=0|zone=1|lastcpupid=0x1fffff) raw: 000fffffc0000000 0000000000000000 ffffffff00000101 0000000000000000 raw: 0000000000000002 0000000000000000 ffffffffffffffff 0000000000000000 page dumped because: nonzero _refcount CPU: 1 PID: 0 Comm: swapper/1 Tainted: G E 6.2.0+ Call Trace: <IRQ> dump_stack_lvl+0x32/0x50 bad_page+0x69/0xf0 free_pcp_prepare+0x260/0x2f0 free_unref_page+0x20/0x1c0 skb_release_data+0x10b/0x1a0 napi_consume_skb+0x56/0x150 net_rx_action+0xf0/0x350 ? __napi_schedule+0x79/0x90 __do_softirq+0xc8/0x2b1 __irq_exit_rcu+0xb9/0xf0 common_interrupt+0x82/0xa0 </IRQ> <TASK> asm_common_interrupt+0x22/0x40 RIP: 0010:default_idle+0xb/0x20

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel flaw is a race in network packet buffer handling. Under the described timing, the kernel can mishandle page reference counts, causing use-after-free or double-free memory errors. The public record shows a fix exists, but does not provide CVSS, exploitation evidence, or a vendor workaround.

Executive priority

Treat this as a kernel maintenance priority, not an emergency from the supplied evidence. Patch during the next appropriate security window, with higher priority for critical network-facing Linux systems.

Technical view

The issue is in skbuff coalescing when a cloned source SKB mixes page-pool and non-page-pool fragments. If the other clone is released during coalescing, fragment accounting can be reset, skipping a needed page reference increment. Later SKB release can free a still-used page, causing use-after-free or double-free.

Likely exposure

Exposure is most likely on Linux systems running affected 5.15, 6.1, 6.2, or 6.3 kernel lines before the referenced stable fixes. The bundle does not identify specific distributions, drivers, workloads, or remote attack preconditions.

Exploitation context

CISA KEV is false, and the supplied sources do not claim active exploitation. The evidence shows a kernel crash/double-free condition observed during investigation, not a public exploit path or reliable attacker workflow.

Researcher notes

The record lacks CVSS, CWE, distribution advisories, and exploitability analysis. Validation should focus on kernel lineage and fix provenance. Avoid assuming remote code execution or active exploitation without additional vendor or KEV evidence.

Mitigation direction

  • Apply Linux kernel updates that include the referenced stable commits.
  • Use distribution vendor kernels when they backport the fix.
  • Prioritize externally exposed or high-throughput networking hosts.
  • If updates are unavailable, check vendor guidance for supported mitigations.

Validation and detection

  • Inventory running Linux kernel versions across servers and appliances.
  • Map each kernel to the affected versions in the CVE record.
  • Confirm fixed packages include one referenced stable commit or an equivalent backport.
  • Review kernel logs for Bad page state, skb_release_data, or napi_consume_skb traces.
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.

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CVE-2023-53186 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
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.

0CVSS vectors
3Timeline events
0ADP providers
5Source links

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.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux53e0961da1c7bbdabd1abebb20de403ec237ec09, 53e0961da1c7bbdabd1abebb20de403ec237ec09, 53e0961da1c7bbdabd1abebb20de403ec237ec09, 53e0961da1c7bbdabd1abebb20de403ec237ec09unaffected
LinuxLinux5.15, 0, 5.15.108, 6.1.25, 6.2.12, 6.3affected
Weakness

CWE details

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