CVE-2024-49861: Linux kernel · bpf: Fix helper writes to read-only maps
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 6.8.0-1023.25~22.04.1 : patch Linux kernel soon.
Data as of 28 Oct 2026, 11:13 UTC
- Patch
- Available – fixed in 6.8.0-1023.25~22.04.1, 6.8.0-1025.30~22.04.1, 6.8.0-1024.26~22.04.1 +29
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 21 Oct 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-7276-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7277-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7301-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7303-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7304-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7303-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7310-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7311-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7303-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7384-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7385-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7386-1 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix helper writes to read-only maps Lonial found an issue that despite user- and BPF-side frozen BPF map (like in case of .rodata), it was still possible to write into it from a BPF program side through specific helpers having ARG_PTR_TO_{LONG,INT} as arguments. In check_func_arg() when the argument is as mentioned, the meta->raw_mode is never set. Later, check_helper_mem_access(), under the case of PTR_TO_MAP_VALUE as register base type, it assumes BPF_READ for the subsequent call to check_map_access_type() and given the BPF map is read-only it succeeds. The helpers really need to be annotated as ARG_PTR_TO_{LONG,INT} | MEM_UNINIT when results are written into them as opposed to read out of them. The latter indicates that it's okay to pass a pointer to uninitialized memory as the memory is written to anyway. However, ARG_PTR_TO_{LONG,INT} is a special case of ARG_PTR_TO_FIXED_SIZE_MEM just with additional alignment requirement. So it is better to just get rid of the ARG_PTR_TO_{LONG,INT} special cases altogether and reuse the fixed size memory types. For this, add MEM_ALIGNED to additionally ensure alignment given these helpers write directly into the args via *<ptr> = val. The .arg*_size has been initialized reflecting the actual sizeof(*<ptr>). MEM_ALIGNED can only be used in combination with MEM_FIXED_SIZE annotated argument types, since in !MEM_FIXED_SIZE cases the verifier does not know the buffer size a priori and therefore cannot blindly write *<ptr> = val.
References
- ubuntu.com/security/CVE-2024-49861 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2024-49861 (opens in a new tab)
- git.kernel.org/linus/32556ce93bc45c730829083cb60f95a2728ea48b (opens in a new tab)
- git.kernel.org/stable/c/a2c8dc7e21803257e762b0bf067fd13e9c995da0 (opens in a new tab)
- git.kernel.org/stable/c/2ed98ee02d1e08afee88f54baec39ea78dc8a23c (opens in a new tab)
- git.kernel.org/stable/c/1e75d25133158b525e0456876e9bcfd6b2993fd5 (opens in a new tab)
- git.kernel.org/stable/c/32556ce93bc45c730829083cb60f95a2728ea48b (opens in a new tab)
- ubuntu.com/security/notices/USN-7276-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7277-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7301-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7303-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7304-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7303-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7310-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7311-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7303-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7384-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7385-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7386-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7384-2 (opens in a new tab)