CVE-2026-53689
Description
libnfs versions prior to 6.0.2 are vulnerable to an integer overflow when connecting to a malicious NFS server, potentially leading to crashes or other issues.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
libnfs versions prior to 6.0.2 are vulnerable to an integer overflow when connecting to a malicious NFS server, potentially leading to crashes or other issues.
Vulnerability
A vulnerability exists in libnfs versions up to and including 6.0.2, specifically in the libnfs_zdr_string function within lib/libnfs-zdr.c. The issue stems from a failure to properly validate a string size received from a crafted NFS server, which can lead to an integer overflow. The fix was introduced in commit 55c18ea [1].
Exploitation
An attacker can exploit this vulnerability by setting up a malicious NFS server. A client using a vulnerable version of libnfs (prior to 6.0.2) would need to establish a connection to this crafted server. The server would then send a string size that is larger than expected, triggering the integer overflow condition.
Impact
Successful exploitation of this vulnerability can lead to an integer overflow. While the exact impact is not detailed in the provided references, such overflows can often result in denial-of-service conditions, such as application crashes, or potentially more severe memory corruption issues depending on how the overflowed value is used.
Mitigation
The vulnerability is addressed in libnfs by commit 55c18ea, which is part of versions after 6.0.2. Users are advised to update to a patched version of libnfs. No specific release date for a patched version is available, but the fix is present in the referenced commit [1].
AI Insight generated on Jun 10, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.
Affected products
2Patches
155c18ea33a83ZDR: check the string size for sanity
1 file changed · +3 −1
lib/libnfs-zdr.c+3 −1 modified@@ -318,7 +318,9 @@ bool_t libnfs_zdr_string(ZDR *zdrs, char **strp, uint32_t maxsize) if (!libnfs_zdr_u_int(zdrs, &size)) { return FALSE; } - + if (size > zdrs->size) { + return FALSE; + } if (zdrs->pos + (int)size > zdrs->size) { return FALSE; }
Vulnerability mechanics
Root cause
"The libnfs_zdr_string function does not properly validate the size of a string received from a network connection, leading to an integer overflow."
Attack vector
An attacker can trigger this vulnerability by connecting to a crafted NFS server. The server sends a string with a size value that causes an integer overflow when processed by the libnfs_zdr_string function. This overflow can lead to a subsequent out-of-bounds read or write.
Affected code
The vulnerability exists in the libnfs_zdr_string function located in the file lib/libnfs-zdr.c. The patch modifies this function to include additional size validation.
What the fix does
The patch adds a check to ensure that the reported string size does not exceed the total buffer size available in the ZDR structure before proceeding with further processing. This prevents the integer overflow that could occur if a large size value was accepted, thereby mitigating the risk of out-of-bounds access.
Preconditions
- networkThe affected component must connect to a network-based NFS server.
- inputThe NFS server must be controlled by an attacker and send a crafted string with an oversized length.
Generated on Jun 10, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.
References
1News mentions
0No linked articles in our index yet.