In the Linux kernel, the following vulnerability has been resolved:
f2fs: compress: fix to call f2fs_wait_on_page_writeback() in f2fs_write_raw_pages()
BUG_ON() will be triggered when writing files concurrently,
because the same page is writtenback multiple times.
1597 void folio_end_writeback(struct folio *folio)
1598 {
......
1618 if (!__folio_end_writeback(folio))
1619 BUG();
......
1625 }
kernel BUG at mm/filemap.c:1619!
Call Trace:
f2fs_write_end_io+0x1a0/0x370
blk_update_request+0x6c/0x410
blk_mq_end_request+0x15/0x130
blk_complete_reqs+0x3c/0x50
__do_softirq+0xb8/0x29b
? sort_range+0x20/0x20
run_ksoftirqd+0x19/0x20
smpboot_thread_fn+0x10b/0x1d0
kthread+0xde/0x110
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x22/0x30
Below is the concurrency scenario:
[Process A] [Process B] [Process C]
f2fs_write_raw_pages()
- redirty_page_for_writepage()
- unlock page()
f2fs_do_write_data_page()
- lock_page()
- clear_page_dirty_for_io()
- set_page_writeback() [1st writeback]
.....
generic_perform_write()
- f2fs_write_begin()
- wait_for_stable_page()
- f2fs_write_end()
- set_page_dirty()
- lock_page()
- f2fs_do_write_data_page()
- set_page_writeback() [2st writeback]
This problem was introduced by the previous commit 7377e853967b ("f2fs:
compress: fix potential deadlock of compress file"). All pagelocks were
released in f2fs_write_raw_pages(), but whether the page was
in the writeback state was ignored in the subsequent writing process.
Let's fix it by waiting for the page to writeback before writing.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (7.8): severity, escalated by confirmed exploitation. This CVE's 7.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 7.8 HIGHCVSS-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 2026-11-04). 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; Track* at high (mission-essential systems).CISA 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 SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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)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