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.
CVE-2019-15794
This high-severity CVE scores 7.1 under NVD CVSS v3. EPSS exploit probability: 1.2%, top 36% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.1
- EG Score
- 7.1(medium)
- EG Risk
- —
- EPSS
- 63.8%
- KEV
- Not listed
Published
April 24, 2020
Last Modified
November 21, 2024
References (8)
- security@ubuntuhttps://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=270d16ae48a4dbf1c7e25e94cc3e38b4bea37635
- security@ubuntuhttps://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=ef81780548d20a786cc77ed4203fca146fd81ce3
- security@ubuntuhttps://usn.ubuntu.com/usn/usn-4208-1
- security@ubuntuhttps://usn.ubuntu.com/usn/usn-4209-1
- af854a3a-2127-422b-91ae-364da2661108https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=270d16ae48a4dbf1c7e25e94cc3e38b4bea37635
- af854a3a-2127-422b-91ae-364da2661108https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=ef81780548d20a786cc77ed4203fca146fd81ce3
- af854a3a-2127-422b-91ae-364da2661108https://usn.ubuntu.com/usn/usn-4208-1
- af854a3a-2127-422b-91ae-364da2661108https://usn.ubuntu.com/usn/usn-4209-1
Vendor Advisories for CVE-2019-15794(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(3)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | linux-image-virtual (5.0.0.37.39) @ disco | 2026-05-27 | ubuntu |
| ubuntu | linux-image-virtual (5.3.0.24.28) @ eoan | 2026-05-27 | ubuntu |
| redhat | kernel-0:4.18.0-348.el8 | 2021-11-09 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(2)
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
Data Freshness Timeline
(refreshed 13× in last 7d / 43× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-22 22:20 UTCEG score recompute
- 2026-07-22 14:05 UTCEPSS rescore
- 2026-07-21 15:22 UTCEPSS rescore
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- 2026-07-19 13:54 UTCOSV refresh
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- 2026-07-02 16:56 UTCEPSS rescore
- 2026-07-02 00:01 UTCOSV refresh
- 2026-07-01 15:03 UTCEPSS rescore
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- 2026-06-30 23:20 UTCEPSS rescore
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- 2026-06-14 23:15 UTCEPSS rescore
- 2026-06-14 23:15 UTCEPSS rescore
- 2026-06-14 03:43 UTCOSV refresh
- 2026-06-13 22:58 UTCEPSS rescore
- 2026-06-12 23:09 UTCEPSS rescore
- 2026-06-11 13:58 UTCEPSS rescore
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- 2026-05-31 00:14 UTCEPSS rescore
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- 2026-05-29 13:42 UTCEPSS rescore
- 2026-05-28 13:43 UTCEPSS rescore
- 2026-05-27 13:38 UTCEPSS rescore
- 2026-05-27 04:18 UTCEG score recompute
- 2026-05-27 04:18 UTCVendor advisory
- 2026-05-27 04:18 UTCGHSA enrichment
- 2026-05-26 13:42 UTCEPSS rescore
- 2026-05-26 13:42 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
Publicly available exploits
(1 reference)Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.
- Exploit-DBEDB-47692✓ verifiedFirst seen Nov 20, 2019
Ubuntu 19.10 - ubuntu-aufs-modified mmap_region() Breaks Refcounting in overlayfs/shiftfs Error Path
Open source ↗
Frequently asked(5)
What is CVE-2019-15794?
When was CVE-2019-15794 disclosed?
Is CVE-2019-15794 actively exploited?
What is the CVSS score of CVE-2019-15794?
How do I remediate CVE-2019-15794?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2019-15794
Is Your Infrastructure Affected by CVE-2019-15794?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.