CVE-2026-84372: Predis: Redis command injection and denial of service via CRLF smuggling in pipelined commands on aggregate connections

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.7%, percentile 54: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 54% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes predis/predis (Composer (PHP)) >= 3.0.0-RC1, < 3.3.0, fixed in 3.3.0. Check your lockfile, including transitive dependencies.

What it is

Predis is a flexible and feature-complete Redis and Valkey client for PHP. From version 3.0.0-RC1 until version 3.3.0, pipeline handling on aggregate cluster and replication connections reparses an already serialized RESP buffer in AbstractAggregateConnection::write() by splitting it with explode("\r\n") instead of honoring RESP length prefixes. Attacker-controlled keys or values containing CRLF sequences can therefore be interpreted by Command::deserializeCommand() as additional commands. On cluster connections, ClusterStrategy::getFakeKey() can route injected keyless commands using the literal fake key value "key", permitting operations such as shard-wide cache deletion, targeted data modification, data reads, or node disruption. On replication connections, malformed reparsing can throw an uncaught exception and repeatedly terminate affected requests. Only pipeline() reaches this vulnerable path; transaction() and MULTI are not affected. This issue is fixed in version 3.3.0.

From the GitHub advisory

Summary

An improper CRLF neutralization flaw in Predis' pipeline handling on aggregate connections lets an unauthenticated attacker who can influence any pipelined argument — a value or a key, e.g. a URL slug used as a cache key — smuggle arbitrary Redis commands into the connection.

- On cluster connections (cluster option, incl. client-side sharding) this is remote command injection: shard-wide FLUSHDB, targeted DEL/SET, same-slot key theft via GET, cache poisoning, and possible node/cluster outage. - On replication connections (replication option) it is a reliable, repeatable denial of service (uncaught fatal error) triggered by any value containing \r\n.

Details

When a pipeline is executed over an aggregate connection, AbstractAggregateConnection::write() re-parses the already-serialized pipeline buffer with explode("\r\n") instead of honoring RESP length prefixes:

Weakness type: CWE-93.

Product: predis/predis (Composer (PHP)) · Assigned by: GitHub_M · Published: 2026-09-01

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.73% probability of exploitation activity in the next 30 days; percentile 54.

Timeline

• 2026-09-01 — CVE record published by GitHub_M
• 2026-09-02 — CVE record last updated
• 2026-09-08 — GitHub-reviewed advisory GHSA-w6f5-v2h6-g786 published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-w6f5-v2h6-g786 github.com
2. CVE.org record CVE-2026-84372 cve.org
3. NVD entry CVE-2026-84372 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com
4. github.com github.com
5. github.com github.com

Critical Composer (PHP) advisories · Today’s Security Digest