ptrace: slightly saner 'get_dumpable()' logic
In the Linux kernel, the following vulnerability has been resolved: ptrace: slightly saner 'get_dumpable()' logic The 'dumpability' of a task is fundamentally about the memory image of the task - the concept comes from whether it can core dump or not - and makes no sense when you don't have an associated mm. And almost all users do in fact use it only for the case where the task has a mm pointer. But we have one odd special case: ptrace_may_access() uses 'dumpable' to check various other things entirely independently of the MM (typically explicitly using flags like PTRACE_MODE_READ_FSCREDS). Including for threads that no longer have a VM (and maybe never did, like most kernel threads). It's not what this flag was designed for, but it is what it is. The ptrace code does check that the uid/gid matches, so you do have to be uid-0 to see kernel thread details, but this means that the traditional "drop capabilities" model doesn't make any difference for this all. Make it all make a *bit* more sense by saying that if you don't have a MM pointer, we'll use a cached "last dumpability" flag if the thread ever had a MM (it will be zero for kernel threads since it is never set), and require a proper CAP_SYS_PTRACE capability to override.
02 / AFFECTED SOFTWARE
Affected packages
550 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: ptrace: slightly saner 'get_dumpable()' logic The 'dumpability' of a task is fundamentally about the memory image of the task - the concept comes from whether it can core dump or not - and makes no sense when you don't have an associated mm. And almost all users do in fact use it only for the case where the task has a mm pointer. But we have one odd special case: ptrace_may_access() uses 'dumpable' to check various other things entirely independently of the MM (typically explicitly using flags like PTRACE_MODE_READ_FSCREDS). Including for threads that no longer have a VM (and maybe never did, like most kernel threads). It's not what this flag was designed for, but it is what it is. The ptrace code does check that the uid/gid matches, so you do have to be uid-0 to see kernel thread details, but this means that the traditional "drop capabilities" model doesn't make any difference for this all. Make it all make a *bit* more sense by saying that if you don't have a MM pointer, we'll use a cached "last dumpability" flag if the thread ever had a MM (it will be zero for kernel threads since it is never set), and require a proper CAP_SYS_PTRACE capability to override.
05 / REFERENCES
Further evidence
- http://www.openwall.com/lists/oss-security/2026/05/15/9
- http://www.openwall.com/lists/oss-security/2026/05/20/14
- http://www.openwall.com/lists/oss-security/2026/05/20/16
- https://access.redhat.com/errata/RHSA-2026:19521
- https://access.redhat.com/errata/RHSA-2026:19540
- https://access.redhat.com/errata/RHSA-2026:19568
- https://access.redhat.com/errata/RHSA-2026:19569
- https://access.redhat.com/errata/RHSA-2026:19664
- https://access.redhat.com/errata/RHSA-2026:19666
- https://access.redhat.com/errata/RHSA-2026:19705
- https://access.redhat.com/errata/RHSA-2026:19711
- https://access.redhat.com/errata/RHSA-2026:19875
- https://access.redhat.com/errata/RHSA-2026:20051
- https://access.redhat.com/errata/RHSA-2026:20054
- https://access.redhat.com/errata/RHSA-2026:20129
- https://access.redhat.com/errata/RHSA-2026:20130
- https://access.redhat.com/errata/RHSA-2026:20299
- https://access.redhat.com/errata/RHSA-2026:20593
- https://access.redhat.com/errata/RHSA-2026:21701
- https://access.redhat.com/errata/RHSA-2026:21702
- https://access.redhat.com/errata/RHSA-2026:23468
- https://access.redhat.com/errata/RHSA-2026:23469
- https://access.redhat.com/errata/RHSA-2026:23470
- https://access.redhat.com/errata/RHSA-2026:23471
- https://access.redhat.com/errata/RHSA-2026:24814
- https://access.redhat.com/errata/RHSA-2026:33486
- https://access.redhat.com/security/cve/CVE-2026-46333
- https://bugzilla.redhat.com/show_bug.cgi?id=2477802
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- https://git.kernel.org/stable/c/01363cb3fbd0238ffdeb09f53e9039c9edf8a730
- https://git.kernel.org/stable/c/15b828a46f305ae9f05a7c16914b3ce273474205
- https://git.kernel.org/stable/c/2a93a4fac7b6051d3be7cd1b015fe7320cd0404d
- https://git.kernel.org/stable/c/31e62c2ebbfdc3fe3dbdf5e02c92a9dc67087a3a
- https://git.kernel.org/stable/c/4709234fd1b95136ceb789f639b1e7ea5de1b181
- https://git.kernel.org/stable/c/6e5b51e74a40d377bcd3081dd33fbaa0e1aa7e3d
- https://git.kernel.org/stable/c/8f907d345bae8f4b3f004c5abc56bf2dfb851ea7
- https://git.kernel.org/stable/c/93d4ba49d18e3d7fb41a9927c2d0cca5e9dfefd6
- https://github.com/0xdeadbeefnetwork/ssh-keysign-pwn/
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46333.json
- https://lists.debian.org/debian-lts-announce/2026/05/msg00032.html
- https://lists.debian.org/debian-lts-announce/2026/05/msg00035.html
- https://nvd.nist.gov/vuln/detail/CVE-2026-46333
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46333.json