Linux: Use After Free
CVE-2026-68198 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. The record lists versions a1bac650b2d6b1baab1f3e78e2e007a6e2948dde, 2132a6db05846dd2318857d00e0c1291f9e41b29, 17ff29cd8dbc977c97788a5f7c011ec807b58242 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 0.27% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to a1bac650b2d6b1baab1f3e78e2e007a6e2948dde or 2132a6db05846dd2318857d00e0c1291f9e41b29 or 17ff29cd8dbc977c97788a5f7c011ec807b58242 or 64af6534a085f49d6ed33338a19ab9cf0d0523c9, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | bdcd81707973cf8aa9305337166f8ee842a050d4 up to, but not including, a1bac650b2d6b1baab1f3e78e2e007a6e2948dde; bdcd81707973cf8aa9305337166f8ee842a050d4 up to, but not including, 2132a6db05846dd2318857d00e0c1291f9e41b29; bdcd81707973cf8aa9305337166f8ee842a050d4 up to, but not including, 17ff29cd8dbc977c97788a5f7c011ec807b58242; bdcd81707973cf8aa9305337166f8ee842a050d4 up to, but not including, 64af6534a085f49d6ed33338a19ab9cf0d0523c9; bdcd81707973cf8aa9305337166f8ee842a050d4 up to, but not including, b5d618fd61b9069b4c0a6b487022dd3117ad5acc; bdcd81707973cf8aa9305337166f8ee842a050d4 up to, but not including, 18965470d41e69d3fc10eb62afae29d10f4cdfd1; bdcd81707973cf8aa9305337166f8ee842a050d4 up to, but not including, a3313111b5d9046af60b370c93eec105b27380c1; bdcd81707973cf8aa9305337166f8ee842a050d4 up to, but not including, ba7debb4dd6427386862220e8335a53a4bfc235d; and 1 more ranges | a1bac650b2d6b1baab1f3e78e2e007a6e2948dde, 2132a6db05846dd2318857d00e0c1291f9e41b29, 17ff29cd8dbc977c97788a5f7c011ec807b58242, 64af6534a085f49d6ed33338a19ab9cf0d0523c9, b5d618fd61b9069b4c0a6b487022dd3117ad5acc, 18965470d41e69d3fc10eb62afae29d10f4cdfd1 |
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
- AdjacentThe attacker must be on the same local network segment.
- 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:A/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: wifi: ath6kl: fix use-after-free in aggr_reset_state() The aggr_reset_state() function uses timer_delete() (non-synchronous) for the aggregation timer before proceeding to delete TID state and before the structure is freed by callers like aggr_module_destroy(). If the timer callback (aggr_timeout) is executing when aggr_reset_state() is called, the callback will continue to access aggr_conn fields like rx_tid[] and stat[] which may be freed immediately after by kfree(aggr_info->aggr_conn) in aggr_module_destroy(). Additionally, the timer callback can re-arm itself via mod_timer() while aggr_reset_state() is running, creating a more complex race condition. Use timer_delete_sync() instead to ensure any running timer callback has completed before returning.
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.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
- git.kernel.org/stable/c/17ff29cd8dbc977c97788a5f7c011ec807b58242
- git.kernel.org/stable/c/18965470d41e69d3fc10eb62afae29d10f4cdfd1
- git.kernel.org/stable/c/2132a6db05846dd2318857d00e0c1291f9e41b29
- git.kernel.org/stable/c/64af6534a085f49d6ed33338a19ab9cf0d0523c9
- git.kernel.org/stable/c/a1bac650b2d6b1baab1f3e78e2e007a6e2948dde
- git.kernel.org/stable/c/a3313111b5d9046af60b370c93eec105b27380c1
- git.kernel.org/stable/c/b5d618fd61b9069b4c0a6b487022dd3117ad5acc
- git.kernel.org/stable/c/ba7debb4dd6427386862220e8335a53a4bfc235d
Recent Use After Free vulnerabilities
- 7.8 High severity
- 9.8 Critical severity
- 7.5 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
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