CVE-2026-43864
NULL Pointer Dereference in Mutt Email Client
Publication date: 2026-05-04
Last updated on: 2026-05-04
Assigner: MITRE
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| muttmua | mutt | to 2.3.2 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-476 | The product dereferences a pointer that it expects to be valid but is NULL. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is a NULL pointer dereference in the show_sig_summary() function of the Mutt email client before version 2.3.2.
Specifically, when the error code is GPG_ERR_NO_PUBKEY, the key variable becomes NULL. The function does not check if the key is NULL before trying to access key->subkeys->expires, which leads to a crash.
The issue is fixed by adding a check to safely handle NULL keys before dereferencing them.
How can this vulnerability impact me? :
This vulnerability can cause the Mutt email client to crash when processing certain signature summaries involving missing public keys.
Because it is a NULL pointer dereference leading to a crash, it results in a denial of service (DoS) condition for the user.
The CVSS score of 2.5 indicates a low severity impact, requiring local access with high attack complexity and user interaction.
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, update the Mutt email client to version 2.3.2 or later where the NULL pointer dereference in the show_sig_summary() function has been fixed.
The fix ensures that the function safely handles NULL keys by checking for NULL before dereferencing, preventing crashes caused by the vulnerability.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability is a NULL pointer dereference in the show_sig_summary() function of the Mutt email client before version 2.3.2. Detection involves identifying if you are running a vulnerable version of Mutt.
You can check the installed version of Mutt on your system by running the following command:
- mutt -v
If the version is earlier than 2.3.2, your system is potentially vulnerable.
Since the vulnerability causes a NULL pointer dereference leading to a crash when processing certain GPG keys, monitoring Mutt crashes or logs for errors related to show_sig_summary or GPG_ERR_NO_PUBKEY may also help detect exploitation attempts.