CVE-2023-27601
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedOpenSIPS is a Session Initiation Protocol (SIP) server implementation. Prior to versions 3.1.7 and 3.2.4, OpenSIPS crashes when a malformed SDP body is received and is processed by the `delete_sdp_line` function in the sipmsgops module. This issue can be reproduced by calling the function with an SDP body that does not terminate by a line feed (i.e. `\n`). The vulnerability was found while performing black-box fuzzing against an OpenSIPS server running a configuration that made use of the functions `codec_delete_except_re` and `codec_delete_re`. The same issue was also discovered while performing coverage guided fuzzing on the function `codec_delete_except_re`. The crash happens because the function `delete_sdp_line` expects that an SDP line is terminated by a line feed (`\n`): By abusing this vulnerability, an attacker is able to crash the server. It affects configurations containing functions that rely on the affected code, such as the function `codec_delete_except_re`. Due to the sanity check that is performed in the `del_lump` function, exploitation of this issue will generate an `abort` in the lumps processing function, resulting in a Denial of Service. This issue has been fixed in versions 3.1.7 and 3.2.4.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysisThe application accepts input without confirming it is well-formed or within expected bounds, so malformed data can push the program into states its author never anticipated. Attackers probe these gaps to trigger crashes, bypass logic, or feed tainted values into more dangerous operations downstream. Remediating it well means validating and normalising every input at the boundary against a strict allow-list — not merely filtering known-bad values.
General guidance for the improper input validation class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 3.1.7>= 3.2.0, < 3.2.4CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped3.1.73.2.4
OpenSIPS 3.1.7 or 3.2.4 (depending on your current minor version branch)
- 1. Identify the current OpenSIPS version by running 'opensips -V' or checking the package manager
- 2. Determine the appropriate upgrade path: if on 3.1.x line, upgrade to 3.1.7; if on 3.2.x line, upgrade to 3.2.4
- 3. Back up the current OpenSIPS configuration files (typically in /etc/opensips/)
- 4. Stop the OpenSIPS service: 'systemctl stop opensips' or 'service opensips stop'
- 5. Upgrade OpenSIPS using the package manager (e.g., 'apt-get update && apt-get install opensips' or 'yum update opensips') or compile from source using the fixed release
- 6. Verify the new version is installed: 'opensips -V'
- 7. Start the OpenSIPS service: 'systemctl start opensips' or 'service opensips start'
- 8. Test that the sipmsgops module functions (codec_delete_re, codec_delete_except_re) work correctly with valid SDP bodies
Generated from the published advisory — verify against the referenced sources before acting.
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Free · runs locallyCheck whether your project pulls in CVE-2023-27601 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-27601 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
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- Version or environment caveats, and links to real fixes
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