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CVE Record

CVE-2025-38588: ipv6: prevent infinite loop in rt6_nlmsg_size()

In the Linux kernel, the following vulnerability has been resolved: ipv6: prevent infinite loop in rt6_nlmsg_size() While testing prior patch, I was able to trigger an infinite loop in rt6_nlmsg_size() in the following place: list_for_each_entry_rcu(sibling, &f6i->fib6_siblings, fib6_siblings) { rt6_nh_nlmsg_size(sibling->fib6_nh, &nexthop_len); } This is because fib6_del_route() and fib6_add_rt2node() uses list_del_rcu(), which can confuse rcu readers, because they might no longer see the head of the list. Restart the loop if f6i->fib6_nsiblings is zero.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel IPv6 bug where route-message size calculation can get stuck in an infinite loop. The likely business impact is availability risk: affected systems may hang or spend excessive CPU in kernel networking paths. The source bundle does not provide CVSS, exploitability, or proof of active attacks.

Executive priority

Handle in normal kernel patch governance unless affected systems are critical network infrastructure or show stability symptoms. No source indicates active exploitation, but kernel availability issues can still create operational disruption.

Technical view

CVE-2025-38588 is in rt6_nlmsg_size(), which iterates IPv6 fib6_siblings under RCU. The CVE notes list_del_rcu() use in fib6_del_route() and fib6_add_rt2node() can confuse readers so they may miss the list head. The kernel fix restarts the loop when f6i->fib6_nsiblings is zero.

Likely exposure

Exposure is limited to Linux systems running affected kernel versions with IPv6 routing code present. The bundled CVE data lists affected Linux kernel ranges and multiple stable kernel commit references, but does not identify specific distributions beyond a Debian LTS advisory reference.

Exploitation context

The bundle does not show CISA KEV listing, active exploitation, public exploit code, or remote exploit details. Treat this as a potential denial-of-service class kernel networking issue until vendor advisories clarify practical trigger conditions.

Researcher notes

Evidence supports an RCU list traversal infinite-loop fix in Linux IPv6 routing. Missing details include CVSS, CWE, exact attack prerequisites, and distribution-specific package versions except the Debian LTS advisory reference. Avoid claiming exploitability beyond denial-of-service potential from the described infinite loop.

Mitigation direction

  • Inventory Linux kernel versions across internet-facing and internal systems.
  • Apply vendor kernel updates that include the referenced stable fixes.
  • Prioritize systems using IPv6 routing, containers, or network-heavy workloads.
  • Review Debian LTS guidance if using Debian-derived systems.
  • If patching is delayed, monitor vendor guidance for supported mitigations.

Validation and detection

  • Compare running kernel versions against vendor advisories for CVE-2025-38588.
  • Confirm patched kernels include one of the referenced stable commits or distribution backports.
  • Check whether IPv6 is enabled and actively used on critical systems.
  • Review kernel and network telemetry for unexplained hangs or CPU saturation.
  • Document any unpatched systems with owner, exposure, and patch date.
Prepared
Confidence
medium
Sources
9

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

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CVE-2025-38588 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
1ADP providers
8Source 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.

ADP provider summaries

CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxd0ec61c9f3583b76aebdbb271f5c0d3fcccd48b2, 52da02521ede55fb86546c3fffd9377b3261b91f, 34a949e7a0869dfa31a40416d2a56973fae1807b, d9ccb18f83ea2bb654289b6ecf014fd267cc988b, d9ccb18f83ea2bb654289b6ecf014fd267cc988b, d9ccb18f83ea2bb654289b6ecf014fd267cc988b, 11edcd026012ac18acee0f1514db3ed1b160fc6f, 6.1.128, 6.6.75, 6.12.2, 6.11.11unaffected
LinuxLinux6.13, 0, 6.1.148, 6.6.102, 6.12.42, 6.15.10, 6.16.1, 6.17affected
Weakness

CWE details

No CWE listed

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