Linux: Use After Free
CVE-2024-57979 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 785c78ed0d39d1717cca3ef931d3e51337b5e90e, 1a7735ab2cb9747518a7416fb5929e85442dec62, c4041b6b0a7a3def8cf3f3d6120ff337bc4c40f7 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 785c78ed0d39d1717cca3ef931d3e51337b5e90e or 1a7735ab2cb9747518a7416fb5929e85442dec62 or c4041b6b0a7a3def8cf3f3d6120ff337bc4c40f7 or 91932db1d96b2952299ce30c1c693d834d10ace6, whichever matches your release line, or a later version.
- Update Linux Kernel to 3.3 or 3.5 or 5.4.291 or 5.10.235, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | d953e0e837e65ecc1ddaa4f9560f7925878a0de6 up to, but not including, 785c78ed0d39d1717cca3ef931d3e51337b5e90e; d953e0e837e65ecc1ddaa4f9560f7925878a0de6 up to, but not including, 1a7735ab2cb9747518a7416fb5929e85442dec62; d953e0e837e65ecc1ddaa4f9560f7925878a0de6 up to, but not including, c4041b6b0a7a3def8cf3f3d6120ff337bc4c40f7; d953e0e837e65ecc1ddaa4f9560f7925878a0de6 up to, but not including, 91932db1d96b2952299ce30c1c693d834d10ace6; d953e0e837e65ecc1ddaa4f9560f7925878a0de6 up to, but not including, cd3bbcb6b3a7caa5ce67de76723b6d8531fb7f64; d953e0e837e65ecc1ddaa4f9560f7925878a0de6 up to, but not including, 7e5ee3281dc09014367f5112b6d566ba36ea2d49; d953e0e837e65ecc1ddaa4f9560f7925878a0de6 up to, but not including, 85241f7de216f8298f6e48540ea13d7dcd100870; d953e0e837e65ecc1ddaa4f9560f7925878a0de6 up to, but not including, c79a39dc8d060b9e64e8b0fa9d245d44befeefbe; and 7 more ranges | 785c78ed0d39d1717cca3ef931d3e51337b5e90e, 1a7735ab2cb9747518a7416fb5929e85442dec62, c4041b6b0a7a3def8cf3f3d6120ff337bc4c40f7, 91932db1d96b2952299ce30c1c693d834d10ace6, cd3bbcb6b3a7caa5ce67de76723b6d8531fb7f64, 7e5ee3281dc09014367f5112b6d566ba36ea2d49 |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | all versions | Not stated |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Linux | Linux Kernel | 3.2.40 up to, but not including, 3.3; 3.4.87 up to, but not including, 3.5; 3.8.1 up to, but not including, 5.4.291; 5.5 up to, but not including, 5.10.235; 5.11 up to, but not including, 5.15.179; 5.16 up to, but not including, 6.1.129; 6.2 up to, but not including, 6.6.76; 6.7 up to, but not including, 6.12.13; and 1 more ranges | 3.3, 3.5, 5.4.291, 5.10.235, 5.15.179, 6.1.129 |
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
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- 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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: pps: Fix a use-after-free On a board running ntpd and gpsd, I'm seeing a consistent use-after-free in sys_exit() from gpsd when rebooting: pps pps1: removed ------------[ cut here ]------------ kobject: '(null)' (00000000db4bec24): is not initialized, yet kobject_put() is being called. WARNING: CPU: 2 PID: 440 at lib/kobject.c:734 kobject_put+0x120/0x150 CPU: 2 UID: 299 PID: 440 Comm: gpsd Not tainted 6.11.0-rc6-00308-gb31c44928842 #1 Hardware name: Raspberry Pi 4 Model B Rev 1.1 (DT) pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : kobject_put+0x120/0x150 lr : kobject_put+0x120/0x150 sp : ffffffc0803d3ae0 x29: ffffffc0803d3ae0 x28: ffffff8042dc9738 x27: 0000000000000001 x26: 0000000000000000 x25: ffffff8042dc9040 x24: ffffff8042dc9440 x23: ffffff80402a4620 x22: ffffff8042ef4bd0 x21: ffffff80405cb600 x20: 000000000008001b x19: ffffff8040b3b6e0 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 696e6920746f6e20 x14: 7369203a29343263 x13: 205d303434542020 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000 x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: kobject_put+0x120/0x150 cdev_put+0x20/0x3c __fput+0x2c4/0x2d8 ____fput+0x1c/0x38 task_work_run+0x70/0xfc do_exit+0x2a0/0x924 do_group_exit+0x34/0x90 get_signal+0x7fc/0x8c0 do_signal+0x128/0x13b4 do_notify_resume+0xdc/0x160 el0_svc+0xd4/0xf8 el0t_64_sync_handler+0x140/0x14c el0t_64_sync+0x190/0x194 ---[ end trace 0000000000000000 ]--- ...followed by more symptoms of corruption, with similar stacks: refcount_t: underflow; use-after-free. kernel BUG at lib/list_debug.c:62! Kernel panic - not syncing: Oops - BUG: Fatal exception This happens because pps_device_destruct() frees the pps_device with the embedded cdev immediately after calling cdev_del(), but, as the comment above cdev_del() notes, fops for previously opened cdevs are still callable even after cdev_del() returns. I think this bug has always been there: I can't explain why it suddenly started happening every time I reboot this particular board. In commit d953e0e837e6 ("pps: Fix a use-after free bug when unregistering a source."), George Spelvin suggested removing the embedded cdev. That seems like the simplest way to fix this, so I've implemented his suggestion, using __register_chrdev() with pps_idr becoming the source of truth for which minor corresponds to which device. But now that pps_idr defines userspace visibility instead of cdev_add(), we need to be sure the pps->dev refcount can't reach zero while userspace can still find it again. So, the idr_remove() call moves to pps_unregister_cdev(), and pps_idr now holds a reference to pps->dev. pps_core: source serial1 got cdev (251:1) <...> pps pps1: removed pps_core: unregistering pps1 pps_core: deallocating pps1
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
Patches and release notes
- git.kernel.org/stable/c/1a7735ab2cb9747518a7416fb5929e85442dec62
- git.kernel.org/stable/c/785c78ed0d39d1717cca3ef931d3e51337b5e90e
- git.kernel.org/stable/c/7e5ee3281dc09014367f5112b6d566ba36ea2d49
- git.kernel.org/stable/c/85241f7de216f8298f6e48540ea13d7dcd100870
- git.kernel.org/stable/c/91932db1d96b2952299ce30c1c693d834d10ace6
- git.kernel.org/stable/c/c4041b6b0a7a3def8cf3f3d6120ff337bc4c40f7
- git.kernel.org/stable/c/c79a39dc8d060b9e64e8b0fa9d245d44befeefbe
- git.kernel.org/stable/c/cd3bbcb6b3a7caa5ce67de76723b6d8531fb7f64
Other references
- lists.debian.org/debian-lts-announce/2025/03/msg00028.html
- lists.debian.org/debian-lts-announce/2025/05/msg00030.html
- cert-portal.siemens.com/productcert/html/ssa-019113.html
- cert-portal.siemens.com/productcert/html/ssa-265688.html
- cert-portal.siemens.com/productcert/html/ssa-457936.html
- cert-portal.siemens.com/productcert/html/ssa-784472.html
Recent Use After Free vulnerabilities
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- 9.8 Critical severity
- 7.8 High severity
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