CVE-2021-32675: DoS vulnerability in Redis
Noroxi assessment
Priority: Monitor (action score 35/100)
- Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
- Probability of exploitation in the next 30 days: 16% (FIRST EPSS); higher than 96.9% of all records.
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: redis (AlmaLinux:8) 6.0.9-5.module_el8.4.0+2584+1bb0d2aa, 5.0.3-5.module_el8.5.0+66+fc19ec12, 5.0.3-5.module_el8.4.0+2583+b9845322; redis-devel (AlmaLinux:8) 5.0.3-5.module_el8.4.0+2583+b9845322, 6.0.9-5.module_el8.4.0+2584+1bb0d2aa, 6.0.9-5.module_el8.5.0+67+a3c431d9; redis-doc (AlmaLinux:8) 6.0.9-5.module_el8.4.0+2584+1bb0d2aa, 5.0.3-5.module_el8.4.0+2583+b9845322.
- Mentioned 2 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to redis (AlmaLinux:8) 6.0.9-5.module_el8.4.0+2584+1bb0d2aa, 5.0.3-5.module_el8.5.0+66+fc19ec12, 5.0.3-5.module_el8.4.0+2583+b9845322; redis-devel (AlmaLinux:8) 5.0.3-5.module_el8.4.0+2583+b9845322, 6.0.9-5.module_el8.4.0+2584+1bb0d2aa, 6.0.9-5.module_el8.5.0+67+a3c431d9; redis-doc (AlmaLinux:8) 6.0.9-5.module_el8.4.0+2584+1bb0d2aa, 5.0.3-5.module_el8.4.0+2583+b9845322 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
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.
- Published
- Oct 4, 2021
- Updated
- Jun 16, 2026
- EPSS
- 16.0% · 96th percentile
- CWE
- CWE-770
Report tools
Action score
35
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 5 / 30 · 16.0%
CNA vs NVD score
- NVD
- 7.5
- CNA · GitHub_M
- 7.5
- agree
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.
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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.
We use this product, ask for helpAffected 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.
| Vendor | Product | CPE |
|---|---|---|
| redis | redis | cpe:2.3:a:redis:redis |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| netapp | management services for element software | cpe:2.3:a:netapp:management_services_for_element_software |
| netapp | management services for netapp hci | cpe:2.3:a:netapp:management_services_for_netapp_hci |
| oracle | communications operations monitor | cpe:2.3:a:oracle:communications_operations_monitor |
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Run a port scanAffected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- redis redis5.0.0 and later · before 5.0.14
- redis redis6.0.0 and later · before 6.0.16
- redis redis6.2.0 and later · before 6.2.6
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
redis redis
- < 5.0.14, >= 6.0.0, < 6.0.16, >= 6.2.0, < 6.2.6affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | redis | before 6.0.9-5.module_el8.4.0+2584+1bb0d2aa | 6.0.9-5.module_el8.4.0+2584+1bb0d2aa |
| AlmaLinux:8 | redis | before 5.0.3-5.module_el8.5.0+66+fc19ec12 | 5.0.3-5.module_el8.5.0+66+fc19ec12 |
| AlmaLinux:8 | redis | before 5.0.3-5.module_el8.4.0+2583+b9845322 | 5.0.3-5.module_el8.4.0+2583+b9845322 |
| AlmaLinux:8 | redis | before 6.0.9-5.module_el8.5.0+67+a3c431d9 | 6.0.9-5.module_el8.5.0+67+a3c431d9 |
| AlmaLinux:8 | redis-devel | before 5.0.3-5.module_el8.4.0+2583+b9845322 | 5.0.3-5.module_el8.4.0+2583+b9845322 |
| AlmaLinux:8 | redis-devel | before 6.0.9-5.module_el8.4.0+2584+1bb0d2aa | 6.0.9-5.module_el8.4.0+2584+1bb0d2aa |
| AlmaLinux:8 | redis-devel | before 6.0.9-5.module_el8.5.0+67+a3c431d9 | 6.0.9-5.module_el8.5.0+67+a3c431d9 |
| AlmaLinux:8 | redis-devel | before 5.0.3-5.module_el8.5.0+66+fc19ec12 | 5.0.3-5.module_el8.5.0+66+fc19ec12 |
| AlmaLinux:8 | redis-doc | before 6.0.9-5.module_el8.4.0+2584+1bb0d2aa | 6.0.9-5.module_el8.4.0+2584+1bb0d2aa |
| AlmaLinux:8 | redis-doc | before 5.0.3-5.module_el8.4.0+2583+b9845322 | 5.0.3-5.module_el8.4.0+2583+b9845322 |
| Alpine:v3.11 | redis | from 5.0.0 · before 5.0.14-r0 | 5.0.14-r0 |
| Alpine:v3.13 | redis | from 5.0.0 · before 6.0.16-r0 | 6.0.16-r0 |
| Alpine:v3.14 | redis | from 5.0.0 · before 6.2.6-r0 | 6.2.6-r0 |
| Debian:10 | redis | before 5:5.0.14-1+deb10u1 | 5:5.0.14-1+deb10u1 |
| Debian:11 | redis | before 5:6.0.16-1+deb11u1 | 5:6.0.16-1+deb11u1 |
| Debian:12 | redis | before 5:6.0.16-1 | 5:6.0.16-1 |
| Debian:9 | redis | before 3:3.2.6-3+deb9u8 | 3:3.2.6-3+deb9u8 |
| openSUSE:Leap 15.3 | redis | before 6.0.14-6.8.1 | 6.0.14-6.8.1 |
| openSUSE:Tumbleweed | redis | before 6.2.6-1.1 | 6.2.6-1.1 |
| Red Hat:enterprise_linux:8::appstream | redis | before 0:5.0.3-5.module+el8.4.0+12927+b9845322 | 0:5.0.3-5.module+el8.4.0+12927+b9845322 |
| Red Hat:enterprise_linux:8::appstream | redis | before 0:6.0.9-5.module+el8.4.0+12929+1bb0d2aa | 0:6.0.9-5.module+el8.4.0+12929+1bb0d2aa |
| Red Hat:enterprise_linux:8::appstream | redis-debuginfo | before 0:5.0.3-5.module+el8.4.0+12927+b9845322 | 0:5.0.3-5.module+el8.4.0+12927+b9845322 |
| Red Hat:enterprise_linux:8::appstream | redis-debuginfo | before 0:6.0.9-5.module+el8.4.0+12929+1bb0d2aa | 0:6.0.9-5.module+el8.4.0+12929+1bb0d2aa |
| Red Hat:enterprise_linux:8::appstream | redis-debugsource | before 0:6.0.9-5.module+el8.4.0+12929+1bb0d2aa | 0:6.0.9-5.module+el8.4.0+12929+1bb0d2aa |
+24
Same product
redis: all recordsOther highest-scoring records for the same primary product.
- CVE-2022-0543It was discovered, that redis, a persistent key-value database, due to a packaging issue, is prone to a (Debian-specific) Lua sandbox escapeKEV100Now
- CVE-2025-49844Redis Lua Use-After-Free may lead to remote code execution64This week
- CVE-2023-36824Heap overflow in COMMAND GETKEYS and ACL evaluation in Redis58Plan
Published before and after this one in the same product
- ← EarlierCVE-2021-32628Oct 4, 2021 · Vulnerability in handling large ziplists34Monitor
- ← EarlierCVE-2021-32672Oct 4, 2021 · Vulnerability in Lua Debugger in Redis18Monitor
- Later →CVE-2021-32687Oct 4, 2021 · Integer overflow issue with intsets in Redis31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| almalinux:redis | 5.0.3-5.module_el8.4.0+2583+b9845322 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:redis-devel | 5.0.3-5.module_el8.5.0+66+fc19ec12 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:redis-doc | 5.0.3-5.module_el8.4.0+2583+b9845322 · AlmaLinux:8 | Package registry (OSV) |
| alpine:redis | 5.0.14-r0 · Alpine:v3.11 | Package registry (OSV) |
| debian:redis | 5:6.0.16-1 · Debian:12 | Package registry (OSV) |
| opensuse:redis | 6.0.14-6.8.1 · openSUSE:Leap 15.3 | Package registry (OSV) |
| red hat:redis | 0:5.0.3-5.module+el8.4.0+12927+b9845322 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:redis-debuginfo | 0:5.0.3-5.module+el8.4.0+12927+b9845322 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:redis-debugsource | 0:5.0.3-5.module+el8.4.0+12927+b9845322 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:redis-devel | 0:5.0.3-5.module+el8.4.0+12927+b9845322 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:redis-doc | 0:5.0.3-5.module+el8.4.0+12927+b9845322 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:rh-redis5-redis | 0:5.0.5-3.el7 · Red Hat:rhel_software_collections:3::el7 | Package registry (OSV) |
| red hat:rh-redis5-redis-debuginfo | 0:5.0.5-3.el7 · Red Hat:rhel_software_collections:3::el7 | Package registry (OSV) |
| rocky linux:redis | 0:5.0.3-5.module+el8.5.0+657+2674830e · Rocky Linux:8 | Package registry (OSV) |
| suse:redis | 6.0.14-6.8.1 · SUSE:Linux Enterprise Module for Server Applications 15 SP2 | Package 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
- Proof-of-concept repository on GitHub ×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.
| Source | Kind | Date |
|---|---|---|
| Proof-of-concept repository on GitHub | stars:0 | 2026-09-09 |
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.
- Published
- First PoC+1800 d
- TodayOct 31, 2026+1853 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
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 researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
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
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-21-0989 · Dec 13, 2021(IBM Güvenlik Bildirimi)
- TR-21-0801 · Oct 5, 2021(Redis Güvenlik Zafiyeti)
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-770 · Allocation of Resources Without Limits or ThrottlingCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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.
Attack patterns (CAPEC)
- FloodingCAPEC-125likelihood: High · Medium
- Excessive AllocationCAPEC-130likelihood: Medium · Medium
- XML Ping of the DeathCAPEC-147likelihood: Low · Medium
- Exponential Data ExpansionCAPEC-197likelihood: High · Medium
- Serialized Data Parameter BlowupCAPEC-229likelihood: High · High
- Serialized Data with Nested PayloadsCAPEC-230likelihood: Medium · High
- Oversized Serialized Data PayloadsCAPEC-231likelihood: Medium · High
- HTTP DoSCAPEC-469Low
ATT&CK techniques
- Network Denial of Service:Direct Network FloodT1498.001
- Network Denial of Service:Reflection AmplificationT1498.002
- Endpoint Denial of ServiceT1499
- Endpoint Denial of Service: OS Exhaustion FloodT1499.001
- Endpoint Denial of Service:Service Exhaustion FloodT1499.002
- Endpoint Denial of Service:Application Exhaustion FloodT1499.003
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (9 more)Show less
- github.com/redis/redis/security/advisories/GHSA-f6pw-v9gw-v64p
- lists.apache.org/thread.html/ra603ff6e04549d7f290f61f9b11e2d2e4dba693b05ff053f4ec6bc47%40%3Cnotifications.geode.apache.org%3E
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HTYQ5ZF37HNGTZWVNJD3VXP7I6MEEF42/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VL5KXFN3ATM7IIM7Q4O4PWTSRGZ5744Z/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WR5WKJWXD4D6S3DJCZ56V74ESLTDQRAB/
- security.gentoo.org/glsa/202209-17
- security.netapp.com/advisory/ntap-20211104-0003/
- www.debian.org/security/2021/dsa-5001
- www.oracle.com/security-alerts/cpuapr2022.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.