CVE-2021-33912
What it is
libspf2 before 1.2.11 has a four-byte heap-based buffer overflow that might allow remote attackers to execute arbitrary code (via an unauthenticated e-mail message from anywhere on the Internet) with a crafted SPF DNS record, because of incorrect sprintf usage in SPF_record_expand_data in spf_expand.c. The vulnerable code may be part of the supply chain of a site's e-mail infrastructure (e.g., with additional configuration, Exim can use libspf2; the Postfix web site links to unofficial patches for use of libspf2 with Postfix; older versions of spfquery relied on libspf2) but most often is not.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 9.6% chance of exploitation in the next 30 days (EPSS).
- Fix
- No patch or advisory is linked yet. Look at mitigations or restrict exposure.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 9.6% in the next 30 days (EPSS).
- Severity: 9.8 CRITICAL (CVSS).
- Fix: none linked yet, which raises it.
Details
- Published
- Last modified
- Exploit probability
- 9.6% · EPSS, next 30 days
- Weakness
- CWE-787 · Out-of-bounds write
- Record status
- Modified
Affected
- libspf2 Project libspf2 < 1.2.11
- Debian Linux 9.0
Attack profile CVSS 3.1 · 9.8
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2021-33912.md and follow it. Check whether this project is affected by CVE-2021-33912. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
References
- https://github.com/shevek/libspf2/tree/8131fe140704eaae695e76b5cd09e39bd1dd220b
- https://lists.debian.org/debian-lts-announce/2022/01/msg00015.html
- https://nathanielbennett.com/blog/libspf2-cve-jan-2022-disclosure
- https://security.gentoo.org/glsa/202401-22
- https://github.com/shevek/libspf2/tree/8131fe140704eaae695e76b5cd09e39bd1dd220b
- https://lists.debian.org/debian-lts-announce/2022/01/msg00015.html
- https://nathanielbennett.com/blog/libspf2-cve-jan-2022-disclosure
- https://security.gentoo.org/glsa/202401-22