Linux: Use After Free
CVE-2026-64132 is a critical-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 769723124b7c3b2bfea4cf68ad292698b87c8d01, 24de676da63c1122d2c13b0d546238b66d1b4e62, 5af905aa8e91ff8d94572a1e089558f21dcf24ed as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.49% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Linux to 769723124b7c3b2bfea4cf68ad292698b87c8d01 or 24de676da63c1122d2c13b0d546238b66d1b4e62 or 5af905aa8e91ff8d94572a1e089558f21dcf24ed or e46e6bc97fb1f339730ff1ba74267fbf48e7a422, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.92 or 6.18.34 or 7.0.11, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | f655c78d6225f585ef60a9d93ffb79d507ff3ad3 up to, but not including, 769723124b7c3b2bfea4cf68ad292698b87c8d01; f655c78d6225f585ef60a9d93ffb79d507ff3ad3 up to, but not including, 24de676da63c1122d2c13b0d546238b66d1b4e62; f655c78d6225f585ef60a9d93ffb79d507ff3ad3 up to, but not including, 5af905aa8e91ff8d94572a1e089558f21dcf24ed; f655c78d6225f585ef60a9d93ffb79d507ff3ad3 up to, but not including, e46e6bc97fb1f339730ff1ba74267fbf48e7a422; 6.9 | 769723124b7c3b2bfea4cf68ad292698b87c8d01, 24de676da63c1122d2c13b0d546238b66d1b4e62, 5af905aa8e91ff8d94572a1e089558f21dcf24ed, e46e6bc97fb1f339730ff1ba74267fbf48e7a422 |
| Linux | Linux Kernel | 6.9 up to, but not including, 6.12.92; 6.13 up to, but not including, 6.18.34; 6.19 up to, but not including, 7.0.11; 7.1 | 6.12.92, 6.18.34, 7.0.11 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: ipv6: ioam: refresh hdr pointer before ioam6_event() Reported by Sashiko: In ipv6_hop_ioam(), the hdr pointer is initialized to point into the skb's linear data buffer. Later, the code calls skb_ensure_writable(), which might reallocate the buffer: if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len)) goto drop; /* Trace pointer may have changed */ trace = (struct ioam6_trace_hdr *)(skb_network_header(skb) + optoff + sizeof(*hdr)); ioam6_fill_trace_data(skb, ns, trace, true); ioam6_event(IOAM6_EVENT_TRACE, dev_net(skb->dev), GFP_ATOMIC, (void *)trace, hdr->opt_len - 2); If the skb is cloned or lacks sufficient linear headroom, skb_ensure_writable() will invoke pskb_expand_head(), which reallocates the skb's data buffer and frees the old one, invalidating pointers to it. While the code recalculates the trace pointer immediately after the call to skb_ensure_writable(), it fails to recalculate the hdr pointer. This patch fixes the above by recalculating the hdr pointer before passing hdr->opt_len to ioam6_event(), so that we avoid any UaF.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Use After Free vulnerabilities
- 8.8 High severity
- 9.8 Critical severity
- 7.8 High severity
- 9.8 Critical severity
- 8.8 High severity
- 8.8 High severity
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