CVE-2021-28090
CVE-2021-28090 is a medium-severity vulnerability in Torproject Tor with a CVSS 3.x base score of 5.3. 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: Medium (CVSS 3.x base score 5.3)
- CVSS v2: 5.0
- EPSS exploit prediction: 2% (79th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-617
- Affected product: Torproject Tor
- Published:
- Last modified:
Description
Tor before 0.4.5.7 allows a remote attacker to cause Tor directory authorities to exit with an assertion failure, aka TROVE-2021-002.
Frequently asked questions
- What is CVE-2021-28090?
- Tor before 0.4.5.7 allows a remote attacker to cause Tor directory authorities to exit with an assertion failure, aka TROVE-2021-002.
- How severe is CVE-2021-28090?
- CVE-2021-28090 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
- Is CVE-2021-28090 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-28090?
- CVE-2021-28090 primarily affects Torproject Tor. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2021-28090?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2021-28090 published?
- CVE-2021-28090 was published on 2021-03-19 and last updated on 2026-06-17.
References
- https://blog.torproject.org/node/2009
- https://bugs.torproject.org/tpo/core/tor/40316
- https://gitlab.torproject.org/tpo/core/tor/-/issues/40316
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HPDXB2GZHG3VNOTWSXQ3QZVHNV76WCU5/
- https://security.gentoo.org/glsa/202107-25
Affected products (6)
- cpe:2.3:a:torproject:tor:*:*:*:*:*:*:*:*
- cpe:2.3:a:torproject:tor:0.4.4.0:alpha:*:*:*:*:*:*
- cpe:2.3:a:torproject:tor:0.4.4.1:alpha:*:*:*:*:*:*
- cpe:2.3:a:torproject:tor:0.4.4.2:alpha:*:*:*:*:*:*
- cpe:2.3:a:torproject:tor:0.4.4.3:alpha:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
More vulnerabilities in Torproject Tor
- CVE-2022-33903 — High (CVSS 7.5): Tor 0.4.7.x before 0.4.7.8 allows a denial of service via the wedging of RTT estimation.
- CVE-2021-38385 — High (CVSS 7.5): Tor before 0.3.5.16, 0.4.5.10, and 0.4.6.7 mishandles the relationship between batch-signature verification and…
- CVE-2021-34550 — High (CVSS 7.5): An issue was discovered in Tor before 0.4.6.5, aka TROVE-2021-006. The v3 onion service descriptor parsing allows…
- CVE-2021-34549 — High (CVSS 7.5): An issue was discovered in Tor before 0.4.6.5, aka TROVE-2021-005. Hashing is mishandled for certain retrieval of…
- CVE-2021-34548 — High (CVSS 7.5): An issue was discovered in Tor before 0.4.6.5, aka TROVE-2021-003. An attacker can forge RELAY_END or RELAY_RESOLVED to…
- CVE-2021-28089 — High (CVSS 7.5): Tor before 0.4.5.7 allows a remote participant in the Tor directory protocol to exhaust CPU resources on a target, aka…
All CVEs affecting Torproject Tor →
Other CWE-617 (Reachable Assertion) vulnerabilities
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- 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.