CyberSecBulletin
CVE-2026-52982NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-52982 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 5af290c86fa81ddbc86a08d54229af5daa40c6a4, 24831b0b2ada9fef18d1f486b7b7c444ee5ba637, 423b5b86e14e190f6e3161eb5f2ea5f908295ba7 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 0.54% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Linux to 5af290c86fa81ddbc86a08d54229af5daa40c6a4 or 24831b0b2ada9fef18d1f486b7b7c444ee5ba637 or 423b5b86e14e190f6e3161eb5f2ea5f908295ba7 or 5db090ca07b28a63fb1499690cf19a3f3adafacb, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.258 or 5.15.209 or 6.1.175 or 6.6.141, whichever matches your release line, or a later version.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 5af290c86fa81ddbc86a08d54229af5daa40c6a4; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 24831b0b2ada9fef18d1f486b7b7c444ee5ba637; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 423b5b86e14e190f6e3161eb5f2ea5f908295ba7; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 5db090ca07b28a63fb1499690cf19a3f3adafacb; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 30cf9829d09ca958279c937af8e35495cd2f1e09; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 6999d70e0eda39af029fa1891c48f0a8832b09d5; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 4dd7eb94f79486b77ca6b4c8676aedbc465dc802; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 23f0e34c64acba15cad4d23e50f41f533da195fa; and 1 more ranges5af290c86fa81ddbc86a08d54229af5daa40c6a4, 24831b0b2ada9fef18d1f486b7b7c444ee5ba637, 423b5b86e14e190f6e3161eb5f2ea5f908295ba7, 5db090ca07b28a63fb1499690cf19a3f3adafacb, 30cf9829d09ca958279c937af8e35495cd2f1e09, 6999d70e0eda39af029fa1891c48f0a8832b09d5
LinuxLinux Kernel2.6.12.1 up to, but not including, 5.10.258; 5.11 up to, but not including, 5.15.209; 5.16 up to, but not including, 6.1.175; 6.2 up to, but not including, 6.6.141; 6.7 up to, but not including, 6.12.91; 6.13 up to, but not including, 6.18.33; 6.19 up to, but not including, 7.0.10; 2.6.12; and 1 more ranges5.10.258, 5.15.209, 6.1.175, 6.6.141, 6.12.91, 6.18.33

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: net: usb: rtl8150: fix use-after-free in rtl8150_start_xmit() syzbot reported a KASAN slab-use-after-free read in rtl8150_start_xmit() when accessing skb->len for tx statistics after usb_submit_urb() has been called: BUG: KASAN: slab-use-after-free in rtl8150_start_xmit+0x71f/0x760 drivers/net/usb/rtl8150.c:712 Read of size 4 at addr ffff88810eb7a930 by task kworker/0:4/5226 The URB completion handler write_bulk_callback() frees the skb via dev_kfree_skb_irq(dev->tx_skb). The URB may complete on another CPU in softirq context before usb_submit_urb() returns in the submitter, so by the time the submitter reads skb->len the skb has already been queued to the per-CPU completion_queue and freed by net_tx_action(): CPU A (xmit) CPU B (USB completion softirq) ------------ ------------------------------ dev->tx_skb = skb; usb_submit_urb() --+ |-------> write_bulk_callback() | dev_kfree_skb_irq(dev->tx_skb) | net_tx_action() | napi_skb_cache_put() <-- free netdev->stats.tx_bytes | += skb->len; <-- UAF read Fix it by caching skb->len before submitting the URB and using the cached value when updating the tx_bytes counter. The pre-existing tx_bytes semantics are preserved: the counter tracks the original frame length (skb->len), not the ETH_ZLEN/USB-alignment padded "count" value that is handed to the device. Changing that would be a user-visible accounting change and is out of scope for this UAF fix.

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.

More Use After Free vulnerabilities (CWE-416)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

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