CVE-2021-20286
CVE-2021-20286 is a low-severity vulnerability in Redhat Libnbd with a CVSS 3.x base score of 2.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-617.
Key facts
- Severity: Low (CVSS 3.x base score 2.7)
- CVSS v2: 4.0
- EPSS exploit prediction: 1% (62nd percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-617
- Affected product: Redhat Libnbd
- Published:
- Last modified:
Description
A flaw was found in libnbd 1.7.3. An assertion failure in nbd_unlocked_opt_go in ilb/opt.c may lead to denial of service.
Frequently asked questions
- What is CVE-2021-20286?
- A flaw was found in libnbd 1.7.3. An assertion failure in nbd_unlocked_opt_go in ilb/opt.c may lead to denial of service.
- How severe is CVE-2021-20286?
- CVE-2021-20286 has a CVSS 3.x base score of 2.7, rated low severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
- Is CVE-2021-20286 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-20286?
- CVE-2021-20286 primarily affects Redhat Libnbd. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2021-20286?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2021-20286 published?
- CVE-2021-20286 was published on 2021-03-15 and last updated on 2026-06-17.
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1934727
- https://gitlab.com/nbdkit/libnbd/-/commit/fb4440de9cc76e9c14bd3ddf3333e78621f40ad0
Affected products (2)
- cpe:2.3:a:redhat:libnbd:*:*:*:*:*:*:*:*
- cpe:2.3:o:redhat:enterprise_linux:8.3.0:*:*:*:advanced_virtualization:*:*:*
More vulnerabilities in Redhat Libnbd
- CVE-2019-14842 — Critical (CVSS 9.8): Structured reply is a feature of the newstyle NBD protocol allowing the server to send a reply in chunks. A bounds…
- CVE-2023-5871 — Medium (CVSS 5.3): A flaw was found in libnbd, due to a malicious Network Block Device (NBD), a protocol for accessing Block Devices such…
- CVE-2023-5215 — Medium (CVSS 5.3): A flaw was found in libnbd. A server can reply with a block size larger than 2^63 (the NBD spec states the size is a…
- CVE-2022-0485 — Medium (CVSS 4.8): A flaw was found in the copying tool `nbdcopy` of libnbd. When performing multi-threaded copies using asynchronous nbd…
All CVEs affecting Redhat Libnbd →
Other CWE-617 (Reachable Assertion) vulnerabilities
- CVE-2020-3615 — Critical (CVSS 9.8): Valid deauth/disassoc frames is dropped in case if RMF is enabled and some rouge peer keep on sending rogue…
- CVE-2019-9795 — Critical (CVSS 9.8): A vulnerability where type-confusion in the IonMonkey just-in-time (JIT) compiler could potentially be used by…
- CVE-2026-31739 — High (CVSS 8.8): In the Linux kernel, the following vulnerability has been resolved: crypto: tegra - Add missing CRYPTO_ALG_ASYNC The…
- CVE-2020-12417 — High (CVSS 8.8): Due to confusion about ValueTags on JavaScript Objects, an object may pass through the type barrier, resulting in…
- CVE-2020-6623 — High (CVSS 8.8): stb stb_truetype.h through 1.22 has an assertion failure in stbtt__cff_get_index.
- CVE-2020-6619 — High (CVSS 8.8): stb stb_truetype.h through 1.22 has an assertion failure in stbtt__buf_seek.