Linux: NULL Pointer Dereference
CVE-2024-26950 is a high-severity NULL pointer dereference 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 493aa6bdcffd90a4f82aa614fe4f4db0641b4068, 4be453271a882c8ebc28df3dbf9e4d95e6ac42f5, 09c3fa70f65175861ca948cb2f0f791e666c90e5 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 0.24% 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 493aa6bdcffd90a4f82aa614fe4f4db0641b4068 or 4be453271a882c8ebc28df3dbf9e4d95e6ac42f5 or 09c3fa70f65175861ca948cb2f0f791e666c90e5 or c991567e6c638079304cc15dff28748e4a3c4a37, whichever matches your release line, or a later version.
- Update SIMATIC S7-1500 TM MFP - GNU/Linux subsystem to V1.1.1 or a later version.
- Update Linux Kernel to 5.10.215 or 5.15.154 or 6.1.84 or 6.6.24, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | e7096c131e5161fa3b8e52a650d7719d2857adfd up to, but not including, 493aa6bdcffd90a4f82aa614fe4f4db0641b4068; e7096c131e5161fa3b8e52a650d7719d2857adfd up to, but not including, 4be453271a882c8ebc28df3dbf9e4d95e6ac42f5; e7096c131e5161fa3b8e52a650d7719d2857adfd up to, but not including, 09c3fa70f65175861ca948cb2f0f791e666c90e5; e7096c131e5161fa3b8e52a650d7719d2857adfd up to, but not including, c991567e6c638079304cc15dff28748e4a3c4a37; e7096c131e5161fa3b8e52a650d7719d2857adfd up to, but not including, 93bcc1752c69bb309f4d8cfaf960ef1faeb34996; e7096c131e5161fa3b8e52a650d7719d2857adfd up to, but not including, d44bd323d8bb8031eef4bdc44547925998a11e47; e7096c131e5161fa3b8e52a650d7719d2857adfd up to, but not including, 71cbd32e3db82ea4a74e3ef9aeeaa6971969c86f; 5.6 | 493aa6bdcffd90a4f82aa614fe4f4db0641b4068, 4be453271a882c8ebc28df3dbf9e4d95e6ac42f5, 09c3fa70f65175861ca948cb2f0f791e666c90e5, c991567e6c638079304cc15dff28748e4a3c4a37, 93bcc1752c69bb309f4d8cfaf960ef1faeb34996, d44bd323d8bb8031eef4bdc44547925998a11e47 |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | before V1.1.1 | V1.1.1 |
| Linux | Linux Kernel | 5.6 up to, but not including, 5.10.215; 5.11 up to, but not including, 5.15.154; 5.16 up to, but not including, 6.1.84; 6.2 up to, but not including, 6.6.24; 6.7 up to, but not including, 6.7.12; 6.8 up to, but not including, 6.8.3 | 5.10.215, 5.15.154, 6.1.84, 6.6.24, 6.7.12, 6.8.3 |
| Debian | Debian Linux | 10.0 | Not stated |
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 | 5.5 | Medium | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: wireguard: netlink: access device through ctx instead of peer The previous commit fixed a bug that led to a NULL peer->device being dereferenced. It's actually easier and faster performance-wise to instead get the device from ctx->wg. This semantically makes more sense too, since ctx->wg->peer_allowedips.seq is compared with ctx->allowedips_seq, basing them both in ctx. This also acts as a defence in depth provision against freed peers.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: NULL Pointer Dereference
The product dereferences a pointer that it expects to be valid but is NULL.
How developers prevent this class of flaw
- For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
- Select a programming language that is not susceptible to these issues.
- Check the results of all functions that return a value and verify that the value is non-null before acting upon it.
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/09c3fa70f65175861ca948cb2f0f791e666c90e5
- git.kernel.org/stable/c/493aa6bdcffd90a4f82aa614fe4f4db0641b4068
- git.kernel.org/stable/c/4be453271a882c8ebc28df3dbf9e4d95e6ac42f5
- git.kernel.org/stable/c/71cbd32e3db82ea4a74e3ef9aeeaa6971969c86f
- git.kernel.org/stable/c/93bcc1752c69bb309f4d8cfaf960ef1faeb34996
- git.kernel.org/stable/c/c991567e6c638079304cc15dff28748e4a3c4a37
- git.kernel.org/stable/c/d44bd323d8bb8031eef4bdc44547925998a11e47
Third-party and government advisories
- lists.debian.org/debian-lts-announce/2024/06/msg00017.htmlMailing List, Third Party Advisory
Other references
Recent NULL Pointer Dereference vulnerabilities
- 8.8 High severity
- 7.5 High severity
- 7.8 High severity
- 7.6 High severity
- 7.8 High severity
- 7.5 High severity
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