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NVD / CVE Program· CNA canonical

CVE-2019-15794: Reference counting error in overlayfs/shiftfs error path when used in conjuction with aufs

Noroxi assessment

Priority: Monitor (action score 26/100)

  • Public proof-of-concept code exists (Exploit-DB); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 1.1% (FIRST EPSS); higher than 67.1% of all records.
  • Someone with local access to the system can trigger it. Administrator privileges are required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: linux (Debian:12) 5.16.7-1; bpftool (Red Hat:enterprise_linux:8::baseos) 0:4.18.0-348.el8; bpftool-debuginfo (Red Hat:enterprise_linux:8::baseos) 0:4.18.0-348.el8.

Low priority for now. Upgrade to linux (Debian:12) 5.16.7-1; bpftool (Red Hat:enterprise_linux:8::baseos) 0:4.18.0-348.el8; bpftool-debuginfo (Red Hat:enterprise_linux:8::baseos) 0:4.18.0-348.el8 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Overlayfs in the Linux kernel and shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, both replace vma->vm_file in their mmap handlers. On error the original value is not restored, and the reference is put for the file to which vm_file points. On upstream kernels this is not an issue, as no callers dereference vm_file following after call_mmap() returns an error. However, the aufs patchs change mmap_region() to replace the fput() using a local variable with vma_fput(), which will fput() vm_file, leading to a refcount underflow.

MediumCVSS 6.7 · v3.1—Proof of concept Fix available
Published
Apr 23, 2020
Updated
Jun 16, 2026
EPSS
1.1% · 67th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.1%

CNA vs NVD score

NVD
6.7
CNA · canonical
7.1
0.4 point gap

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2019-15794

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel
canonicalubuntu linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • canonical ubuntu linux18.04
  • canonical ubuntu linux19.10
  • linux linux kernel5.0
  • linux linux kernel5.3

Versions reported by the vendor

Affected version ranges reported by the assigning authority (canonical). Independent of NVD's CPE analysis and usually ahead of it.

  • Ubuntu Linux kernel

    • 5.3 kernel and later · before 5.3.0-24.26affected
    • 5.0 kernel and later · before 5.0.0-37.40affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.16.7-15.16.7-1
Red Hat:enterprise_linux:8::baseosbpftoolbefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseosbpftool-debuginfobefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernelbefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-abi-stablelistsbefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-corebefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-debugbefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-debug-corebefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-debug-debuginfobefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-debug-develbefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-debug-modulesbefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-debug-modules-extrabefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-debuginfobefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-debuginfo-common-aarch64before 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-debuginfo-common-ppc64lebefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-debuginfo-common-s390xbefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-debuginfo-common-x86_64before 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-develbefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-docbefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-modulesbefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-modules-extrabefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-toolsbefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-tools-debuginfobefore 0:4.18.0-348.el80:4.18.0-348.el8
Red Hat:enterprise_linux:8::baseoskernel-tools-libsbefore 0:4.18.0-348.el80:4.18.0-348.el8

+11

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2019-15792Apr 23, 2020 · Type confusion in shiftfs
    31Monitor
  • ← EarlierCVE-2019-15793Apr 23, 2020 · Mishandling of file-system uid/gid with namespaces in shiftfs
    35Monitor
  • Later →CVE-2020-11884Apr 29, 2020 · In the Linux kernel 4.19 through 5.6.7 on the s390 platform, code execution may occur because of a race condition, as demonstrated by code i
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:linux5.16.7-1 · Debian:12Package registry (OSV)
red hat:bpftool0:4.18.0-348.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:bpftool-debuginfo0:4.18.0-348.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel0:4.18.0-348.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-abi-stablelists0:4.18.0-348.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-core0:4.18.0-348.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug0:4.18.0-348.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-core0:4.18.0-348.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-debuginfo0:4.18.0-348.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-devel0:4.18.0-348.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-modules0:4.18.0-348.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-modules-extra0:4.18.0-348.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debuginfo0:4.18.0-348.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Exploit-DB entry ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Exploit-DB entrydos2019-11-20

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. First PoC-156 d
  2. Published
  3. TodayNov 5, 2026+2387 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • Administrator privileges are required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-672 · Operation on a Resource after Expiration or Release

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records