In the Linux kernel, the following vulnerability has been resolved:
mm: krealloc: Fix MTE false alarm in __do_krealloc
This patch addresses an issue introduced by commit 1a83a716ec233 ("mm:
krealloc: consider spare memory for __GFP_ZERO") which causes MTE
(Memory Tagging Extension) to falsely report a slab-out-of-bounds error.
The problem occurs when zeroing out spare memory in __do_krealloc. The
original code only considered software-based KASAN and did not account
for MTE. It does not reset the KASAN tag before calling memset, leading
to a mismatch between the pointer tag and the memory tag, resulting
in a false positive.
Example of the error:
==================================================================
swapper/0: BUG: KASAN: slab-out-of-bounds in __memset+0x84/0x188
swapper/0: Write at addr f4ffff8005f0fdf0 by task swapper/0/1
swapper/0: Pointer tag: [f4], memory tag: [fe]
swapper/0:
swapper/0: CPU: 4 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.
swapper/0: Hardware name: MT6991(ENG) (DT)
swapper/0: Call trace:
swapper/0: dump_backtrace+0xfc/0x17c
swapper/0: show_stack+0x18/0x28
swapper/0: dump_stack_lvl+0x40/0xa0
swapper/0: print_report+0x1b8/0x71c
swapper/0: kasan_report+0xec/0x14c
swapper/0: __do_kernel_fault+0x60/0x29c
swapper/0: do_bad_area+0x30/0xdc
swapper/0: do_tag_check_fault+0x20/0x34
swapper/0: do_mem_abort+0x58/0x104
swapper/0: el1_abort+0x3c/0x5c
swapper/0: el1h_64_sync_handler+0x80/0xcc
swapper/0: el1h_64_sync+0x68/0x6c
swapper/0: __memset+0x84/0x188
swapper/0: btf_populate_kfunc_set+0x280/0x3d8
swapper/0: __register_btf_kfunc_id_set+0x43c/0x468
swapper/0: register_btf_kfunc_id_set+0x48/0x60
swapper/0: register_nf_nat_bpf+0x1c/0x40
swapper/0: nf_nat_init+0xc0/0x128
swapper/0: do_one_initcall+0x184/0x464
swapper/0: do_initcall_level+0xdc/0x1b0
swapper/0: do_initcalls+0x70/0xc0
swapper/0: do_basic_setup+0x1c/0x28
swapper/0: kernel_init_freeable+0x144/0x1b8
swapper/0: kernel_init+0x20/0x1a8
swapper/0: ret_from_fork+0x10/0x20
==================================================================
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (5.5): severity, escalated by confirmed exploitation. This CVE's 5.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 5.5 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 (model v2026.06.15, score date 2026-10-25). 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, and whom BOD 26-04 binds: 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.
The score's inputs: 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