Linux: Use of Externally-Controlled Format String
CVE-2024-35845 is a critical-severity use of externally-controlled format string vulnerability in Linux, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions fabe2db7de32a881e437ee69db32e0de785a6209, 96aa40761673da045a7774f874487cdb50c6a2f7, c855a1a5b7e3de57e6b1b29563113d5e3bfdb89a 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 1.17% chance of exploitation within 30 days, higher than 68% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Linux to fabe2db7de32a881e437ee69db32e0de785a6209 or 96aa40761673da045a7774f874487cdb50c6a2f7 or c855a1a5b7e3de57e6b1b29563113d5e3bfdb89a or 783d413f332a3ebec916664b366c28f58147f82c, 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.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | a9248de42464e546b624e3fc6a8b04b991af3591 up to, but not including, fabe2db7de32a881e437ee69db32e0de785a6209; a9248de42464e546b624e3fc6a8b04b991af3591 up to, but not including, 96aa40761673da045a7774f874487cdb50c6a2f7; a9248de42464e546b624e3fc6a8b04b991af3591 up to, but not including, c855a1a5b7e3de57e6b1b29563113d5e3bfdb89a; a9248de42464e546b624e3fc6a8b04b991af3591 up to, but not including, 783d413f332a3ebec916664b366c28f58147f82c; a9248de42464e546b624e3fc6a8b04b991af3591 up to, but not including, fec14d1cdd92f340b9ba2bd220abf96f9609f2a9; a9248de42464e546b624e3fc6a8b04b991af3591 up to, but not including, 71d4186d470e9cda7cd1a0921b4afda737c6f641; a9248de42464e546b624e3fc6a8b04b991af3591 up to, but not including, ea1d166fae14e05d49ffb0ea9fcd4658f8d3dcea; 5.5 | fabe2db7de32a881e437ee69db32e0de785a6209, 96aa40761673da045a7774f874487cdb50c6a2f7, c855a1a5b7e3de57e6b1b29563113d5e3bfdb89a, 783d413f332a3ebec916664b366c28f58147f82c, fec14d1cdd92f340b9ba2bd220abf96f9609f2a9, 71d4186d470e9cda7cd1a0921b4afda737c6f641 |
| Linux | linux_kernel | a9248de42464; 5.5 | Not stated |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | before V1.1.1 | V1.1.1 |
| 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
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- 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
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H. Scored by CISA (ADP).
Official description
In the Linux kernel, the following vulnerability has been resolved: wifi: iwlwifi: dbg-tlv: ensure NUL termination The iwl_fw_ini_debug_info_tlv is used as a string, so we must ensure the string is terminated correctly before using it.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Externally-Controlled Format String
The product uses a function that accepts a format string as an argument, but the format string originates from an external source.
How developers prevent this class of flaw
- Choose a language that is not subject to this flaw.
- Ensure that all format string functions are passed a static string which cannot be controlled by the user, and that the proper number of arguments are always sent to that function as well. If at all possible, use functions that do not support the %n operator in format strings.
- Run compilers and linkers with high warning levels, since they may detect incorrect usage.
More Use of Externally-Controlled Format String vulnerabilities (CWE-134)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/71d4186d470e9cda7cd1a0921b4afda737c6f641
- git.kernel.org/stable/c/783d413f332a3ebec916664b366c28f58147f82c
- git.kernel.org/stable/c/96aa40761673da045a7774f874487cdb50c6a2f7
- git.kernel.org/stable/c/c855a1a5b7e3de57e6b1b29563113d5e3bfdb89a
- git.kernel.org/stable/c/ea1d166fae14e05d49ffb0ea9fcd4658f8d3dcea
- git.kernel.org/stable/c/fabe2db7de32a881e437ee69db32e0de785a6209
- git.kernel.org/stable/c/fec14d1cdd92f340b9ba2bd220abf96f9609f2a9
Third-party and government advisories
- lists.debian.org/debian-lts-announce/2024/06/msg00017.htmlMailing List, Third Party Advisory
Other references
Recent Use of Externally-Controlled Format String vulnerabilities
- 7.2 High severity
- 8.8 High severity
- 8.1 High severity
- 9.8 Critical severity
Fortinet Multiple Products Format String Exploited
- 8.8 High severity
- 8.8 High severity
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