Redis is an open source, in-memory database that persists on disk. When parsing an incoming Redis Standard Protocol (RESP) request, Redis allocates memory according to user-specified values which determine the number of elements (in the multi-bulk header) and size of each element (in the bulk header). An attacker delivering specially crafted requests over multiple connections can cause the server to allocate significant amount of memory. Because the same parsing mechanism is used to handle authentication requests, this vulnerability can also be exploited by unauthenticated users. The problem is fixed in Redis versions 6.2.6, 6.0.16 and 5.0.14. An additional workaround to mitigate this problem without patching the redis-server executable is to block access to prevent unauthenticated users from connecting to Redis. This can be done in different ways: Using network access control tools like firewalls, iptables, security groups, etc. or Enabling TLS and requiring users to authenticate using client side certificates.
CVE-2021-32675
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 15.8%, top 3% 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
- 7.5
- EG Score
- 7.5(medium)
- EG Risk
- 54(Track)EG Risk 54/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity75% × 45%Exploitation40% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS
- 96.5%
- KEV
- Not listed
Published
October 4, 2021
Last Modified
November 21, 2024
References (20)
- security-advisories@githubhttps://github.com/redis/redis/commit/5674b0057ff2903d43eaff802017eddf37c360f8
- security-advisories@githubhttps://github.com/redis/redis/security/advisories/GHSA-f6pw-v9gw-v64p
- security-advisories@githubhttps://lists.apache.org/thread.html/ra603ff6e04549d7f290f61f9b11e2d2e4dba693b05ff053f4ec6bc47%40%3Cnotifications.geode.apache.org%3E
- security-advisories@githubhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HTYQ5ZF37HNGTZWVNJD3VXP7I6MEEF42/
- security-advisories@githubhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VL5KXFN3ATM7IIM7Q4O4PWTSRGZ5744Z/
- security-advisories@githubhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WR5WKJWXD4D6S3DJCZ56V74ESLTDQRAB/
- security-advisories@githubhttps://security.gentoo.org/glsa/202209-17
- security-advisories@githubhttps://security.netapp.com/advisory/ntap-20211104-0003/
- security-advisories@githubhttps://www.debian.org/security/2021/dsa-5001
- security-advisories@githubhttps://www.oracle.com/security-alerts/cpuapr2022.html
- af854a3a-2127-422b-91ae-364da2661108https://github.com/redis/redis/commit/5674b0057ff2903d43eaff802017eddf37c360f8
- af854a3a-2127-422b-91ae-364da2661108https://github.com/redis/redis/security/advisories/GHSA-f6pw-v9gw-v64p
- af854a3a-2127-422b-91ae-364da2661108https://lists.apache.org/thread.html/ra603ff6e04549d7f290f61f9b11e2d2e4dba693b05ff053f4ec6bc47%40%3Cnotifications.geode.apache.org%3E
- af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HTYQ5ZF37HNGTZWVNJD3VXP7I6MEEF42/
- af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VL5KXFN3ATM7IIM7Q4O4PWTSRGZ5744Z/
Vendor Advisories for CVE-2021-32675(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(8)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | redis-sentinel (2:3.0.6-1ubuntu0.4+esm1) @ xenial | 2026-05-26 | ubuntu |
| redhat | redis-0:3.2.8-5.el7ost | 2021-10-25 | redhat |
| redhat | redis:6-8040020211011082941.522a0ee4 | 2021-10-20 | redhat |
| redhat | redis:5-8010020211011065007.c27ad7f8 | 2021-10-20 | redhat |
| redhat | redis:5-8020020211011071901.4cda2c84 | 2021-10-20 | redhat |
| redhat | rh-redis5-redis-0:5.0.5-3.el7 | 2021-10-20 | redhat |
| redhat | rhacm2/redisgraph-tls-rhel8:v2.3.3-3 | 2021-10-20 | redhat |
| redhat | redis:5-8040020211011074037.522a0ee4 | 2021-10-19 | 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
(9)
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.
- Microsoft MSRCCVE-2021-326752021-10-14
DoS vulnerability in Redis
- Red HatRHSA-2021:3918IMPORTANT2021-10-04
RHSA-2021:3918 — Important
- Red HatRHSA-2021:3925IMPORTANT2021-10-04
RHSA-2021:3925 — Important
- Red HatRHSA-2021:3944IMPORTANT2021-10-04
RHSA-2021:3944 — Important
- Red HatRHSA-2021:3945IMPORTANT2021-10-04
RHSA-2021:3945 — Important
- Red HatRHSA-2021:3946IMPORTANT2021-10-04
RHSA-2021:3946 — Important
- Red HatRHSA-2021:3971IMPORTANT2021-10-04
RHSA-2021:3971 — Important
- Red HatRHSA-2021:3980IMPORTANT2021-10-04
RHSA-2021:3980 — Important
- UbuntuUSN-5221-1MEDIUM
Redis vulnerabilities
Data Freshness Timeline
(refreshed 15× in last 7d / 44× 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.
- 2026-07-23 02:00 UTCEG score recompute
- 2026-07-22 22:48 UTCEG score recompute
- 2026-07-22 14:06 UTCEPSS rescore
- 2026-07-22 14:06 UTCEPSS rescore
- 2026-07-21 15:22 UTCEPSS rescore
- 2026-07-21 15:22 UTCEPSS rescore
- 2026-07-20 17:05 UTCEPSS rescore
- 2026-07-19 14:29 UTCEPSS rescore
- 2026-07-19 14:29 UTCEPSS rescore
- 2026-07-19 02:27 UTCEPSS rescore
- 2026-07-18 10:29 UTCOSV refresh
- 2026-07-18 10:02 UTCEPSS rescore
- 2026-07-18 10:02 UTCEPSS rescore
- 2026-07-16 17:00 UTCEPSS rescore
- 2026-07-16 17:00 UTCEPSS rescore
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- 2026-07-09 19:07 UTCEPSS rescore
- 2026-07-08 15:12 UTCEPSS rescore
- 2026-07-07 13:43 UTCEPSS rescore
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- 2026-07-06 16:25 UTCEPSS rescore
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- 2026-07-04 06:29 UTCEPSS rescore
- 2026-07-01 15:04 UTCEPSS rescore
- 2026-06-30 23:20 UTCEPSS rescore
- 2026-06-30 23:20 UTCEPSS rescore
- 2026-06-30 11:30 UTCOSV refresh
- 2026-06-28 14:05 UTCEPSS rescore
- 2026-06-28 04:54 UTCEPSS rescore
- 2026-06-28 04:54 UTCEPSS rescore
- 2026-06-27 03:06 UTCEPSS rescore
- 2026-06-25 13:48 UTCEPSS rescore
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- 2026-06-21 14:55 UTCEPSS rescore
- 2026-06-21 01:58 UTCEPSS rescore
- 2026-06-21 01:58 UTCEPSS rescore
- 2026-06-19 19:24 UTCEPSS rescore
- 2026-06-19 19:24 UTCEPSS rescore
- 2026-06-18 17:51 UTCEPSS rescore
- 2026-06-18 17:51 UTCEPSS rescore
- 2026-06-17 17:51 UTCEPSS rescore
- 2026-06-16 17:51 UTCEPSS rescore
- 2026-06-16 17:51 UTCEPSS rescore
- 2026-06-15 17:46 UTCEPSS rescore
- 2026-06-13 22:58 UTCEPSS rescore
- 2026-06-13 22:58 UTCEPSS rescore
- 2026-06-12 23:10 UTCEPSS rescore
- 2026-06-12 23:10 UTCEPSS rescore
- 2026-06-12 20:10 UTCOSV refresh
- 2026-06-11 13:58 UTCEPSS rescore
- 2026-06-10 22:16 UTCEPSS rescore
- 2026-06-10 13:20 UTCEPSS rescore
- 2026-06-08 14:15 UTCEPSS rescore
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- 2026-06-07 15:23 UTCEPSS rescore
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- 2026-06-06 13:46 UTCEPSS rescore
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- 2026-06-05 22:45 UTCEPSS rescore
- 2026-06-05 06:09 UTCEPSS rescore
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- 2026-06-04 13:10 UTCEPSS rescore
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- 2026-06-02 20:11 UTCEPSS rescore
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- 2026-05-31 22:29 UTCEPSS rescore
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- 2026-05-31 00:15 UTCEPSS rescore
- 2026-05-31 00:15 UTCEPSS rescore
- 2026-05-29 13:42 UTCEPSS rescore
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- 2026-05-28 13:43 UTCEPSS rescore
- 2026-05-28 13:43 UTCEPSS rescore
- 2026-05-27 13:39 UTCEPSS rescore
- 2026-05-27 13:39 UTCEPSS rescore
- 2026-05-27 13:39 UTCEPSS rescore
- 2026-05-26 13:42 UTCEPSS rescore
- 2026-05-26 09:33 UTCEG score recompute
- 2026-05-26 09:33 UTCVendor advisory
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
Related CVEs(same vendor + same CWE)
Same vendor
10 shownmsrc · redhat
Same CWE
10 shownCWE-770
- CVE-2018-20033EG 9.8CRITICAL
- CVE-2019-11479NVD 7.5EG 9.0EPSS 100%HIGH
- CVE-2019-11478NVD 5.3EG 9.0EPSS 100%MEDIUM
- CVE-2019-10088EG 8.8EPSS 91%HIGH
- CVE-2018-15462EG 8.6HIGH
- CVE-2018-15460EG 8.6HIGH
- CVE-2018-0137EG 8.6HIGH
- CVE-2008-5180NVD 5.3EG 7.9EPSS 99%MEDIUM
- CVE-2019-10094EG 7.8HIGH
- CVE-2018-16865EG 7.8HIGH
Frequently asked(5)
What is CVE-2021-32675?
When was CVE-2021-32675 disclosed?
Is CVE-2021-32675 actively exploited?
What is the CVSS score of CVE-2021-32675?
How do I remediate CVE-2021-32675?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2021-32675
Is Your Infrastructure Affected by CVE-2021-32675?
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