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 .
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-26). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)3 days if the affected system is publicly exposed; 60 days if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it