Linux: Use After Free
CVE-2023-53559 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 82fb41c5de243e7dfa90f32ca58e35adaff56c1d, 7dfe23659f3677c08a60a0056cda2d91a79c15ca, d34c30442d5e53a33cde79ca163320dbe2432cbd 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 0.15% 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 82fb41c5de243e7dfa90f32ca58e35adaff56c1d or 7dfe23659f3677c08a60a0056cda2d91a79c15ca or d34c30442d5e53a33cde79ca163320dbe2432cbd or 0b4d69539fdea138af2befe08893850c89248068, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.14.324 or 4.19.293 or 5.4.255 or 5.10.192, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | f855691975bb06373a98711e4cfe2c224244b536 up to, but not including, 82fb41c5de243e7dfa90f32ca58e35adaff56c1d; f855691975bb06373a98711e4cfe2c224244b536 up to, but not including, 7dfe23659f3677c08a60a0056cda2d91a79c15ca; f855691975bb06373a98711e4cfe2c224244b536 up to, but not including, d34c30442d5e53a33cde79ca163320dbe2432cbd; f855691975bb06373a98711e4cfe2c224244b536 up to, but not including, 0b4d69539fdea138af2befe08893850c89248068; f855691975bb06373a98711e4cfe2c224244b536 up to, but not including, e1e04cc2ef2c0c0866c19f5627149a76c2baae32; f855691975bb06373a98711e4cfe2c224244b536 up to, but not including, 2b05bf5dc437f7891dd409a3eaf5058459391c7a; f855691975bb06373a98711e4cfe2c224244b536 up to, but not including, 78e397a43e1c47321a4679cc49a6c4530bf820b9; f855691975bb06373a98711e4cfe2c224244b536 up to, but not including, 6018a266279b1a75143c7c0804dd08a5fc4c3e0b; and 1 more ranges | 82fb41c5de243e7dfa90f32ca58e35adaff56c1d, 7dfe23659f3677c08a60a0056cda2d91a79c15ca, d34c30442d5e53a33cde79ca163320dbe2432cbd, 0b4d69539fdea138af2befe08893850c89248068, e1e04cc2ef2c0c0866c19f5627149a76c2baae32, 2b05bf5dc437f7891dd409a3eaf5058459391c7a |
| Linux | Linux Kernel | 3.19.1 up to, but not including, 4.14.324; 4.15 up to, but not including, 4.19.293; 4.20 up to, but not including, 5.4.255; 5.5 up to, but not including, 5.10.192; 5.11 up to, but not including, 5.15.128; 5.16 up to, but not including, 6.1.47; 6.2 up to, but not including, 6.4.12; 3.19; and 1 more ranges | 4.14.324, 4.19.293, 5.4.255, 5.10.192, 5.15.128, 6.1.47 |
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 NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: ip_vti: fix potential slab-use-after-free in decode_session6 When ip_vti device is set to the qdisc of the sfb type, the cb field of the sent skb may be modified during enqueuing. Then, slab-use-after-free may occur when ip_vti device sends IPv6 packets. As commit f855691975bb ("xfrm6: Fix the nexthdr offset in _decode_session6.") showed, xfrm_decode_session was originally intended only for the receive path. IP6CB(skb)->nhoff is not set during transmission. Therefore, set the cb field in the skb to 0 before sending packets.
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
- git.kernel.org/stable/c/0b4d69539fdea138af2befe08893850c89248068
- git.kernel.org/stable/c/2b05bf5dc437f7891dd409a3eaf5058459391c7a
- git.kernel.org/stable/c/6018a266279b1a75143c7c0804dd08a5fc4c3e0b
- git.kernel.org/stable/c/78e397a43e1c47321a4679cc49a6c4530bf820b9
- git.kernel.org/stable/c/7dfe23659f3677c08a60a0056cda2d91a79c15ca
- git.kernel.org/stable/c/82fb41c5de243e7dfa90f32ca58e35adaff56c1d
- git.kernel.org/stable/c/d34c30442d5e53a33cde79ca163320dbe2432cbd
- git.kernel.org/stable/c/e1e04cc2ef2c0c0866c19f5627149a76c2baae32
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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