CVE-2023-3603 Processing sftp server read may cause null dereference
A missing allocation check in libssh allows a malicious client to cause a null dereference and crash the SFTP server via large read requests.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2023-3603?
CVE-2023-3603 is a low-severity vulnerability in Fedora Extra Packages for Enterprise Linux 7, published on 21 Jul 2023. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A missing allocation check in sftp server processing read requests may cause a NULL dereference on low-memory conditions. The malicious client can request up to 4GB SFTP reads, causing allocation of up to 4GB buffers, which was not being checked for failure. This will likely crash the authenticated user's sftp server connection (if implemented as forking as recommended). For thread-based servers, this might also cause DoS for legitimate users. Given this code is not in any released versions, no security releases have been issued.
Weakness: CWE-476
Which versions are affected by CVE-2023-3603?
It affects 1 product.
Products include Libssh Libssh.
How do I fix CVE-2023-3603?
No fix has been published for CVE-2023-3603 yet. Limit exposure of the affected software until one is available.
Is CVE-2023-3603 being exploited?
There is no known exploitation of CVE-2023-3603 in the wild and no public exploit code.
Other vulnerabilities in Fedora Extra Packages for Enterprise Linux 7
- CVE-2026-59851 Libssh: libssh: authentication bypass via missing gssapi principal check
- CVE-2025-5987 Libssh: invalid return code for chacha20 poly1305 with openssl backend
- CVE-2025-14821 Libssh: libssh: insecure default configuration leads to local man-in-the-middle attacks on windows
- CVE-2012-4560 Memory corruption in n/a
- CVE-2012-4562 Integer overflow in n/a
Sources
Also known as GHSA-2c4f-vgwr-82q6.