stb: Double Free
CVE-2023-45679 is a high-severity double free vulnerability in stb from Nothings, 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 unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected stb versions: <= 1.22; 1.22 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.51% 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
- Check which version of stb you run against the affected versions below, and install the vendor's latest release.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Nothings | stb | <= 1.22; 1.22 and earlier | Not stated |
| Nothings | Stb Vorbis.c | 1.22 | 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
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- 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:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.3 | High | CNA (github.com) |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
stb_vorbis is a single file MIT licensed library for processing ogg vorbis files. A crafted file may trigger memory allocation failure in `start_decoder`. In that case the function returns early, but some of the pointers in `f->comment_list` are left initialized and later `setup_free` is called on these pointers in `vorbis_deinit`. This issue may lead to code execution.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Double Free
The product calls free() twice on the same memory address.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- Ensure that each allocation is freed only once. After freeing a chunk, set the pointer to NULL to ensure the pointer cannot be freed again. In complicated error conditions, be sure that clean-up routines respect the state of allocation properly. If the language is object oriented, ensure that object destructors delete each chunk of memory only once.
- Use a static analysis tool to find double free instances.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- github.com/nothings/stb/blob/5736b15f7ea0ffb08dd38af21067c314d6a3aae9/stb_vorbis.c#L3660-L3677Third Party Advisory
- github.com/nothings/stb/blob/5736b15f7ea0ffb08dd38af21067c314d6a3aae9/stb_vorbis.c#L4208-L4215Third Party Advisory
- securitylab.github.com/advisories/GHSL-2023-145_GHSL-2023-151_stb_image_h/Third Party Advisory
Other vulnerabilities in stb
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
Recent Double Free vulnerabilities
- 9.8 Critical severity
- 8.8 High severity
- 7.5 High severity
- 7.8 High severity
- 7.1 High severity
- 8.8 High severity
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