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CVE-2026-68157
libceph: guard missing CRUSH type name lookup
Published 2026-08-10 (2 months ago) by the Linux kernel CNA. Subsystem net/ceph. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-68157 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixedDLA-4777-1 · 2026-09-08 · text | 6.1.187-1 | Update the kernel and reboot. DLA-4777-1 shipped the fix on 2026-09-08, in 6.1.187-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.101-1 | Update the kernel and reboot. Fixed in 6.12.101-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.6-1 | Update the kernel and reboot. Fixed in 7.1.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.6-1 | Update the kernel and reboot. Fixed in 7.1.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4745-1 · 2026-08-18 · text | 6.12.101-1~deb12u1 | Update the kernel and reboot. DLA-4745-1 shipped the fix on 2026-08-18, in 6.12.101-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Localized read selection can walk a parent bucket whose name exists in the CRUSH map while its type has no matching entry in type_names. get_immediate_parent() then dereferences a NULL type_cn and passes an invalid pointer into strcmp(), causing a null-ptr-deref. Skip such malformed parent buckets unless both the bucket name and type name metadata are present. This keeps malformed hierarchy data from crashing locality lookup and safely falls back to "not local". [ idryomov: add WARN_ON_ONCE ]
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
net/ceph/osdmap.c
- What this is
- CEPH COMMON CODE (LIBCEPH)MAINTAINERS section matched on net/ceph/ · ceph-devel@vger.kernel.org · Supported
- Kernel module
- libceph
Check it on the machine
grep -w CONFIG_CEPH_LIB /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w libcephPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this as a loadable module. Every release below compiles it as a module on every flavour, so whether the code is in the running kernel depends on whether that module is loaded.
- bookworm, trixie, forky, sid, bookworm · linux-6.12m
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- Build switch
- CONFIG_CEPH_LIB
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-08-10 (2 months ago)source
- CVSS
- 7.5 high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsource recompute it - Attack vector
- network (AV:N)source
- EPSS
- 0.70%, higher than 52.1% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- net/ceph
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.8 | 5.10.265 | cbfcba275326 |
| 5.8 | 5.15.216 | 8ff579ac03d6 |
| 5.8 | 6.1.183 | 6a4b75d90f0c |
| 5.8 | 6.6.148 | c46d82c47afc |
| 5.8 | 6.12.101 | 3767c9f0c1bb |
| 5.8 | 6.18.42 | 4716a64b7cc2 |
| 5.8 | 7.1.6 | db9cc9fd9660 |
| 5.8 | 7.2 | bbeae12fda33 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4777-1 | 2026-09-08 | bookworm 6.1.187-1 | tracker |
| DLA-4745-1 | 2026-08-18 | bookworm 6.12.101-1~deb12u1 | tracker |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:NAttack vector, network
- Malformed CRUSH hierarchy data is delivered to the kernel Ceph client in CEPH_MSG_OSD_MAP over TCP from a monitor or OSD peer, stored in libceph, and later triggers get_immediate_parent() during localized-read target selection on RBD/CephFS client I/O.
- AC:LAttack complexity, low
- A compromised or attacker-controlled Ceph monitor can publish an osdmap whose CRUSH buckets have names but missing type_names entries; once applied, the NULL dereference is reliably hit on subsequent localize-read calc_target() paths without further attacker-controlled timing.
- PR:NPrivileges required, none
- Exploitation requires no privileges on the victim host; any machine acting as a kernel Ceph client that receives a forged osdmap from a cluster peer over the network can be attacked without local capabilities or user-namespace tricks.
- UI:NUser interaction, none
- No victim user action is needed at exploitation time beyond the host already being a Ceph client with localized reads enabled; forged osdmaps are applied automatically and the crash fires on subsequent kernel client read or map-rescan operations.
- S:UScope, unchanged
- Impact is confined to kernel memory on the Ceph client host (crash or potential escalation within that host); it does not cross VM, IOMMU, or sandbox boundaries to other security authorities.
- C:NConfidentiality impact, none
- The failure is a NULL pointer dereference when accessing type_cn->cn_name; there is no out-of-bounds read, use-after-free, or other memory corruption that could disclose kernel data.
- I:NIntegrity impact, none
- The bug causes a NULL pointer dereference crash only; no attacker-controlled write, heap corruption, or control-flow hijack primitive is created by this defect.
- A:HAvailability impact, high
- The NULL pointer dereference in get_immediate_parent() during CRUSH locality lookup causes a kernel oops or panic, denying all service on the affected Ceph client host.