Medium Memory corruption

CVE-2026-33930 — Apache Traffic Server: Buffer overflow via Host field that has a long string value

Apache Traffic Server copies the client Host header into a fixed-size stack buffer without a bound during redirect handling, so an over-long Host header overflows the stack when redirect following is enabled. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3. Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fix the issue.

Published Jul 29, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: apache

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Apache Software Foundation

Traffic Server

CVSS base

5.9

Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Apache Software Foundation Traffic Server).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Apache Software Foundation	Traffic Server	≥ 8.0.0 and ≤ 8.1.9≥ 9.0.0 and < 9.2.15≥ 10.0.0 and < 10.1.4	Vulnerable	NIST National Vulnerability Database
Apache Software Foundation	Traffic Server	≥ 8.0.0 and ≤ 8.1.11≥ 9.0.0 and ≤ 9.2.14≥ 10.0.0 and ≤ 10.1.3	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

High

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
8.2	CVSS 4.0	High	—	—	security@apache.org via NIST National Vulnerability Database
8.2	CVSS 4.0	High	—	—	apache via CVE Program (cve.org) e CISA ADP
5.9	CVSS 3.1	Medium	2.2	3.6	security@apache.org via NIST National Vulnerability Database
5.9	CVSS 3.1	Medium	—	—	apache via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: security@apache.org)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-121 · Stack-based Buffer Overflow

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.

web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

2026
Affected products added · apache software foundation/apache traffic server
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
CVSS changed · 5.9
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Modified
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Jul 29, 2026 · apache

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

1 on the record

lists.apache.org/thread/5prl9glcm9g2swnq9hqxvnokylm1gr6d
Mailing List, Vendor Advisory, vendor-advisory, NIST National Vulnerability Database

Elsewhere on this site

Apache Software Foundation
every CVE for this vendor

Memory corruption
same class

CWE-121
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-65100 Apache Traffic Server: HPACK encoder desynchronizes from the decoder after a failed header encode Jul 29, 2026
High CVE-2026-58188 Apache Traffic Server: Memory-safety and limit-bypass errors across experimental plugins Jul 29, 2026
High CVE-2026-58189 Apache Traffic Server: Plugins resetting the redirect counter enable SSRF amplification Jul 29, 2026
High CVE-2026-58182 Apache Traffic Server: ts_lua plugin has initialization and resource-handling errors Jul 29, 2026
High CVE-2026-58184 Apache Traffic Server: header_rewrite plugin cookie handling can corrupt memory Jul 29, 2026
High CVE-2026-58183 Apache Traffic Server: prefetch plugin can crash on attacker-influenced input Jul 29, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-33930 is "Apache Traffic Server: Buffer overflow via Host field that has a long string value", rated Medium. It affects Traffic Server (Apache Software Foundation); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.9 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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