Linux: Use After Free
CVE-2024-44985 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 b3a3d5333c13a1be57499581eab4a8fc94d57f36, c47e022011719fc5727bca661d662303180535ba, 975f764e96f71616b530e300c1bb2ac0ce0c2596 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 0.88% chance of exploitation within 30 days, higher than 60% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to b3a3d5333c13a1be57499581eab4a8fc94d57f36 or c47e022011719fc5727bca661d662303180535ba or 975f764e96f71616b530e300c1bb2ac0ce0c2596 or 38a21c026ed2cc7232414cb166efc1923f34af17, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.166 or 6.1.107 or 6.6.48 or 6.10.7, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 81d626b00bdba16504eeae9cc891b18e83a9471a up to, but not including, b3a3d5333c13a1be57499581eab4a8fc94d57f36; ee6b1db17f8287b615448488fc37f42bcfe9ece6 up to, but not including, c47e022011719fc5727bca661d662303180535ba; 0c9f227bee11910a49e1d159abe102d06e3745d5 up to, but not including, 975f764e96f71616b530e300c1bb2ac0ce0c2596; 0c9f227bee11910a49e1d159abe102d06e3745d5 up to, but not including, 38a21c026ed2cc7232414cb166efc1923f34af17; 0c9f227bee11910a49e1d159abe102d06e3745d5 up to, but not including, 124b428fe28064c809e4237b0b38e97200a8a4a8; 0c9f227bee11910a49e1d159abe102d06e3745d5 up to, but not including, fc88d6c1f2895a5775795d82ec581afdff7661d1; 0c9f227bee11910a49e1d159abe102d06e3745d5 up to, but not including, 2d5ff7e339d04622d8282661df36151906d0e1c7; 5.15 | b3a3d5333c13a1be57499581eab4a8fc94d57f36, c47e022011719fc5727bca661d662303180535ba, 975f764e96f71616b530e300c1bb2ac0ce0c2596, 38a21c026ed2cc7232414cb166efc1923f34af17, 124b428fe28064c809e4237b0b38e97200a8a4a8, fc88d6c1f2895a5775795d82ec581afdff7661d1 |
| Linux | Linux Kernel | 5.15 up to, but not including, 5.15.166; 5.16 up to, but not including, 6.1.107; 6.2 up to, but not including, 6.6.48; 6.7 up to, but not including, 6.10.7; 6.11 | 5.15.166, 6.1.107, 6.6.48, 6.10.7 |
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 | 9.8 | Critical | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: ipv6: prevent possible UAF in ip6_xmit() If skb_expand_head() returns NULL, skb has been freed and the associated dst/idev could also have been freed. We must use rcu_read_lock() to prevent a possible 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.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/124b428fe28064c809e4237b0b38e97200a8a4a8
- git.kernel.org/stable/c/2d5ff7e339d04622d8282661df36151906d0e1c7
- git.kernel.org/stable/c/38a21c026ed2cc7232414cb166efc1923f34af17
- git.kernel.org/stable/c/975f764e96f71616b530e300c1bb2ac0ce0c2596
- git.kernel.org/stable/c/fc88d6c1f2895a5775795d82ec581afdff7661d1
Other references
Recent Use After Free vulnerabilities
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- 7.8 High severity
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- 7.8 High severity
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- 7.8 High severity
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