high CVSS 8.8 EPSS 1.5%

CVE-2026-23479·Redis vulnerability

Redis is an in-memory data structure store. In redis-server from 7.2.0 until 8.6.3, the unblock client flow does not handle an error return from `processCommandAndResetClient` when re-executing a blocked command. If a blocked client is evicted during this flow, an authenticated attacker can trigger a use-after-free that may lead to remote code execution. This has been patched in version 8.6.3.

Severity
high
Software
Redis
Fixed in
8.6.3
Published

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at 1.5% — higher than 74% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

Affected versions

From: 7.2.0

Until: 8.6.3

Fixed in: 8.6.3

How to fix this CVE

Upgrade Redis to version 8.6.3 or later to patch a critical use-after-free vulnerability in the client unblock flow. Authenticated attackers can exploit improper error handling when a blocked client is evicted, potentially leading to remote code execution. Prioritize this update for all production Redis instances, especially those with restrictive authentication policies that may create a false sense of security.

sudo dnf update redis

Defensia detects this vulnerability

How to check if you are affected

  1. Run `redis-cli INFO server | grep redis_version` to check the currently running Redis version on the server
  2. Verify network exposure: Check if Redis is listening on non-localhost interfaces with `ss -tlnp | grep redis` or inspect the bind configuration in /etc/redis/redis.conf
  3. Search Redis logs for client eviction events: `grep -i 'evicted\|maxmemory' /var/log/redis/*.log` to identify if eviction policies are active
  4. After upgrading, confirm the new version with `redis-cli --version` and restart the service: `sudo systemctl restart redis-server`

FAQ

What is CVE-2026-23479?

CVE-2026-23479 is a use-after-free vulnerability in Redis's client unblock mechanism that occurs when error handling fails during command re-execution on evicted blocked clients. An authenticated attacker can trigger this flaw to achieve remote code execution.

Is CVE-2026-23479 being actively exploited?

No, this vulnerability is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog and no public exploits are available, though the high CVSS score warrants immediate patching.

What versions of Redis are affected by CVE-2026-23479?

Redis versions 7.2.0 through 8.6.2 are vulnerable; version 8.6.3 and later contain the fix.

How do I check if my server is vulnerable to CVE-2026-23479?

Run `redis-cli INFO server` and check the redis_version field; if it shows any version from 7.2.0 to 8.6.2, your instance is affected.

Does Defensia detect CVE-2026-23479?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Redis is installed on a monitored server, CVE-2026-23479 will appear in your dashboard with remediation steps.

Related Redis CVEs

CVE-2022-0543CVSS 10It was discovered, that redis, a persistent key-value database, due to a packaging issue, is prone to a (Debian-specific) Lua sandbox escape, which could result in remote code execution.
CVE-2026-25243CVSS 8.8Redis is an in-memory data structure store. In versions of redis-server up to 8.6.3, the RESTORE command does not properly validate serialized values. An authenticated attacker with permission to execute RESTORE can supply a crafted serialized payload that triggers invalid memory access and may lead to remote code execution. A workaround is to restrict access to the RESTORE command with ACL rules. This is patched in version 8.6.3.
CVE-2018-12326CVSS 8.5Buffer overflow in redis-cli of Redis before 4.0.10 and 5.x before 5.0 RC3 allows an attacker to achieve code execution and escalate to higher privileges via a crafted command line. NOTE: It is unclear whether there are any common situations in which redis-cli is used with, for example, a -h (aka hostname) argument from an untrusted source.
CVE-2026-66373CVSS 8.5Redis before 8.8.0, in the unusual case where an authenticated attacker can execute RESTORE, allows remote code execution via a RESTORE payload where the same NACK (pending entry) is referenced by more than one consumer, because deleting both consumers via XGROUP DELCONSUMER leads to a double free. NOTE: this issue exists because of an incomplete fix for CVE-2026-25243.
CVE-2026-23631CVSS 8.1Redis is an in-memory data structure store. In all versions of redis-server with Lua scripting, an authenticated attacker can exploit the master-replica synchronization mechanism to trigger a use-after-free on replicas where replica-read-only is disabled or can be disabled, which may lead to remote code execution. A workaround is to prevent users from executing Lua scripts or avoid using replicas where replica-read-only is disabled. This is patched in version 8.6.3.

References

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