In the Linux kernel, the following vulnerability has been resolved:
xfrm: also call xfrm_state_delete_tunnel at destroy time for states that were never added
In commit b441cf3f8c4b ("xfrm: delete x->tunnel as we delete x"), I
missed the case where state creation fails between full
initialization (->init_state has been called) and being inserted on
the lists.
In this situation, ->init_state has been called, so for IPcomp
tunnels, the fallback tunnel has been created and added onto the
lists, but the user state never gets added, because we fail before
that. The user state doesn't go through __xfrm_state_delete, so we
don't call xfrm_state_delete_tunnel for those states, and we end up
leaking the FB tunnel.
There are several codepaths affected by this: the add/update paths, in
both net/key and xfrm, and the migrate code (xfrm_migrate,
xfrm_state_migrate). A "proper" rollback of the init_state work would
probably be doable in the add/update code, but for migrate it gets
more complicated as multiple states may be involved.
At some point, the new (not-inserted) state will be destroyed, so call
xfrm_state_delete_tunnel during xfrm_state_gc_destroy. Most states
will have their fallback tunnel cleaned up during __xfrm_state_delete,
which solves the issue that b441cf3f8c4b (and other patches before it)
aimed at. All states (including FB tunnels) will be removed from the
lists once xfrm_state_fini has called flush_work(&xfrm_state_gc_work).
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
- EG Severity
- Not assessed: no CVSS publishedA missing CVSS is not a severity of zero.
- 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
- No SSVC decision: EchelonGraph has not assessed this CVECISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the BOD 26-04 block below.
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” 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