Calling NSS-backed functions that support caching via nscd may call the
nscd client side code and in the GNU C Library version 2.36 under high
load on x86_64 systems, the client may call memcmp on inputs that are
concurrently modified by other processes or threads and crash.
The nscd client in the GNU C Library uses the memcmp function with
inputs that may be concurrently modified by another thread, potentially
resulting in spurious cache misses, which in itself is not a security
issue. However in the GNU C Library version 2.36 an optimized
implementation of memcmp was introduced for x86_64 which could crash
when invoked with such undefined behaviour, turning this into a
potential crash of the nscd client and the application that uses it.
This implementation was backported to the 2.35 branch, making the nscd
client in that branch vulnerable as well. Subsequently, the fix for
this issue was backported to all vulnerable branches in the GNU C
Library repository.
It is advised that distributions that may have cherry-picked the memcpy
SSE2 optimization in their copy of the GNU C Library, also apply the fix
to avoid the potential crash in the nscd client.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (6.2): severity, escalated by confirmed exploitation. This CVE's 6.2 is its impact severity (EG Severity), not escalated.
- EG Severity
- 6.2 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.2% within 30 daysSource: FIRST EPSS. 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 every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade 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 every mission impact level.
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (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