In the Linux kernel, the following vulnerability has been resolved:
jbd2: fix assertion 'jh->b_frozen_data == NULL' failure when journal aborted
Following process will fail assertion 'jh->b_frozen_data == NULL' in
jbd2_journal_dirty_metadata():
jbd2_journal_commit_transaction
unlink(dir/a)
jh->b_transaction = trans1
jh->b_jlist = BJ_Metadata
journal->j_running_transaction = NULL
trans1->t_state = T_COMMIT
unlink(dir/b)
handle->h_trans = trans2
do_get_write_access
jh->b_modified = 0
jh->b_frozen_data = frozen_buffer
jh->b_next_transaction = trans2
jbd2_journal_dirty_metadata
is_handle_aborted
is_journal_aborted // return false
--> jbd2 abort <--
while (commit_transaction->t_buffers)
if (is_journal_aborted)
jbd2_journal_refile_buffer
__jbd2_journal_refile_buffer
WRITE_ONCE(jh->b_transaction,
jh->b_next_transaction)
WRITE_ONCE(jh->b_next_transaction, NULL)
__jbd2_journal_file_buffer(jh, BJ_Reserved)
J_ASSERT_JH(jh, jh->b_frozen_data == NULL) // assertion failure !
The reproducer (See detail in [Link]) reports:
------------[ cut here ]------------
kernel BUG at fs/jbd2/transaction.c:1629!
invalid opcode: 0000 [#1] PREEMPT SMP
CPU: 2 PID: 584 Comm: unlink Tainted: G W
5.19.0-rc6-00115-g4a57a8400075-dirty #697
RIP: 0010:jbd2_journal_dirty_metadata+0x3c5/0x470
RSP: 0018:ffffc90000be7ce0 EFLAGS: 00010202
Call Trace:
__ext4_handle_dirty_metadata+0xa0/0x290
ext4_handle_dirty_dirblock+0x10c/0x1d0
ext4_delete_entry+0x104/0x200
__ext4_unlink+0x22b/0x360
ext4_unlink+0x275/0x390
vfs_unlink+0x20b/0x4c0
do_unlinkat+0x42f/0x4c0
__x64_sys_unlink+0x37/0x50
do_syscall_64+0x35/0x80
After journal aborting, __jbd2_journal_refile_buffer() is executed with
holding @jh->b_state_lock, we can fix it by moving 'is_handle_aborted()'
into the area protected by @jh->b_state_lock.
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. 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: 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.
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