9.8 CVE-2026-52986
Enriched by CISA Patch
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_conntrack_sip: don't use simple_strtoul
Replace unsafe port parsing in epaddr_len(), ct_sip_parse_header_uri(),
and ct_sip_parse_request() with a new sip_parse_port() helper that
validates each digit against the buffer limit, eliminating the use of
simple_strtoul() which assumes NUL-terminated strings.
The previous code dereferenced pointers without bounds checks after
sip_parse_addr() and relied on simple_strtoul() on non-NUL-terminated
skb data. A port that reaches the buffer limit without a trailing
character is also rejected as malformed.
Also get rid of all simple_strtoul() usage in conntrack, prefer a
stricter version instead. There are intentional changes:
- Bail out if number is > UINT_MAX and indicate a failure, same for
too long sequences.
While we do accept 05535 as port 5535, we will not accept e.g.
'sip:10.0.0.1:005060'. While its syntactically valid under RFC 3261,
we should restrict this to not waste cycles when presented with
malformed packets with 64k '0' characters.
- Force base 10 in ct_sip_parse_numerical_param(). This is used to fetch
'expire=' and 'rports='; both are expected to use base-10.
- In nf_nat_sip.c, only accept the parsed value if its within the 1k-64k
range.
- epaddr_len now returns 0 if the port is invalid, as it already does
for invalid ip addresses. This is intentional. nf_conntrack_sip
performs lots of guesswork to find the right parts of the message
to parse. Being stricter could break existing setups.
Connection tracking helpers are designed to allow traffic to
pass, not to block it.
Based on an earlier patch from Jenny Guanni Qu <qguanni@gmail.com>.
https://nvd.nist.gov/vuln/detail/CVE-2026-52986
Categories
CWE-476 : NULL Pointer Dereference
The product dereferences a pointer that it expects to be valid but is NULL. NULL pointer dereferences are frequently resultant from rarely encountered error conditions and race conditions, since these are most likely to escape detection during the testing phases. Common abbreviation for Null Pointer Dereference Common abbreviation for Null Pointer Dereference Common abbreviation for Null Pointer Exception used for access of nil in Go programs This weakness can be detected using dynamic tools and techniques that interact with the software using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The software's operation may slow down, but it should not become unstable, crash, or generate incorrect results. Identify error conditions that are not likely to occur during normal usage and trigger them. For example, run the program under low memory conditions, run with insufficient privileges or permissions, interrupt a transaction before it is completed, or disable connectivity to basic network services such as DNS. Monitor the software for any unexpected behavior. If you trigger an unhandled exception or similar error that was discovered and handled by the application's environment, it may still indicate unexpected conditions that were not handled by the application itself. Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.) Use tools that are integrated duringcompilation to insert runtime error-checking mechanismsrelated to memory safety errors, such as AddressSanitizer(ASan) for C/C++ [REF-1518]. For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished [REF-1484]. Select a programming language that is not susceptible to these issues. Check the results of all functions that return a value and verify that the value is non-null before acting upon it. Identify all variables and data stores that receive information from external sources, and apply input validation to make sure that they are only initialized to expected values. Explicitly initialize all variables and other data stores, either during declaration or just before the first usage. C++ library for LLM inference has NULL pointer dereference if a read operation fails race condition causes a table to be corrupted if a timer activates while it is being modified, leading to resultant NULL dereference; also involves locking. large number of packets leads to NULL dereference packet with invalid error status value triggers NULL dereference Chain: race condition for an argument value, possibly resulting in NULL dereference ssh component for Go allows clients to cause a denial of service (nil pointer dereference) against SSH servers. Chain: Use of an unimplemented network socket operation pointing to an uninitialized handler function (CWE-456) causes a crash because of a null pointer dereference (CWE-476). Chain: race condition (CWE-362) might allow resource to be released before operating on it, leading to NULL dereference (CWE-476) Chain: some unprivileged ioctls do not verify that a structure has been initialized before invocation, leading to NULL dereference Chain: IP and UDP layers each track the same value with different mechanisms that can get out of sync, possibly resulting in a NULL dereference Chain: Use of an unimplemented network socket operation pointing to an uninitialized handler function (CWE-456) causes a crash because of a null pointer dereference (CWE-476) Chain: improper initialization of memory can lead to NULL dereference Chain: game server can access player data structures before initialization has happened leading to NULL dereference Chain: The return value of a function returning a pointer is not checked for success (CWE-252) resulting in the later use of an uninitialized variable (CWE-456) and a null pointer dereference (CWE-476) Chain: a message having an unknown message type may cause a reference to uninitialized memory resulting in a null pointer dereference (CWE-476) or dangling pointer (CWE-825), possibly crashing the system or causing heap corruption. Chain: unchecked return value can lead to NULL dereference SSL software allows remote attackers to cause a denial of service (crash) via a crafted SSL/TLS handshake that triggers a null dereference. Network monitor allows remote attackers to cause a denial of service (crash) via a malformed RADIUS packet that triggers a null dereference. Network monitor allows remote attackers to cause a denial of service (crash) via a malformed Q.931, which triggers a null dereference. Chat client allows remote attackers to cause a denial of service (crash) via a passive DCC request with an invalid ID number, which causes a null dereference. Server allows remote attackers to cause a denial of service (crash) via malformed requests that trigger a null dereference. OS allows remote attackers to cause a denial of service (crash from null dereference) or execute arbitrary code via a crafted request during authentication protocol selection. Game allows remote attackers to cause a denial of service (server crash) via a missing argument, which triggers a null pointer dereference. Network monitor allows remote attackers to cause a denial of service (crash) or execute arbitrary code via malformed packets that cause a NULL pointer dereference. Chain: System call returns wrong value (CWE-393), leading to a resultant NULL dereference (CWE-476).
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
AFFECTED (from MITRE)
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux |
|
| Linux | Linux |
|
| © 2022 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. | ||
CPE
| cpe | start | end |
|---|---|---|
| Configuration 1 | ||
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | >= 2.6.26 | < 5.10.258 |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | >= 5.11 | < 5.15.209 |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | >= 5.16 | < 6.1.175 |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | >= 6.2 | < 6.6.141 |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | >= 6.7 | < 6.12.91 |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | >= 6.13 | < 6.18.33 |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | >= 6.19 | < 7.0.10 |
| cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* | ||
REMEDIATION
Patch
EXPLOITS
Exploit-db.com
| id | description | date | |
|---|---|---|---|
| No known exploits | |||
POC Github
| Url |
|---|
| No known exploits |
Other Nist (github, ...)
| Url |
|---|
| No known exploits |
CAPEC
Common Attack Pattern Enumerations and Classifications
| id | description | severity |
|---|---|---|
| No entry | ||
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