CVE Intelligence
High Injection

CVE-2025-55702 — Apache Traffic Server: An unread Expect: 100-continue request body is framed as a new request

When a client sends a POST with Expect: 100-continue and the origin answers before reading the body, Apache Traffic Server parses the unread body left on the client connection as the next request. An attacker behind a front-end proxy that shares connections to Traffic Server can use this to smuggle requests past the front end and desynchronize responses for other users. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.15, from 10.0.0 through 10.1.4, 10.2.0. Users are recommended to upgrade to version 9.2.16, 10.1.5, or 10.2.1, which fix the issue.

Published Oct 21, 2026 · Updated Oct 22, 2026 · Sources: CVE Program (cve.org) e CISA ADP, NIST National Vulnerability Database, GitHub Security Advisories · CNA: apache

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
  • EPSS 0.3% (30-day exploitation probability)+4
  • Technical severity (high)+6

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
0.33%
ahead of 26% of scored CVEs · Oct 30, 2026
Affects
Apache Software Foundation
Traffic Server
CVSS base
8.7
High · 3 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
No
can an attacker script the kill-chain steps
Technical impact
Total
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.

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

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Apache Software Foundation Traffic Server ≥ 8.0.0 and ≤ 8.1.11≥ 9.0.0 and ≤ 9.2.15≥ 10.0.0 and ≤ 10.1.4version 10.2.0 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
Changed
Confidentiality
High
Integrity
High
Availability
None

Every base score collected

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

ScoreVersionSeverityExpl.ImpactScored by
7.0 CVSS 4.0 High — — security@apache.org via NIST National Vulnerability Database
7.0 CVSS 4.0 High — — apache via CVE Program (cve.org) e CISA ADP
8.7 CVSS 3.1 High 2.2 5.8 security@apache.org via NIST National Vulnerability Database
8.7 CVSS 3.1 High — — GitHub, Inc. via GitHub Security Advisories
8.7 CVSS 3.1 High — — apache via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N (score shown at the top: security@apache.org)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-444 · HTTP Request Smuggling

Other CVEs with this weakness →

EPSS over time FIRST

Oct 22, 2026 → Oct 30, 2026 · 9 reading(s) · max 0.33%

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).
  • Look for parameters with command/query metacharacters and unexpected child processes of the service.
web/proxy/WAF logsnetwork IDS/IPSapplication logsendpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

  • 2026
  • SSVC assessment updated
    Oct 22, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · Received → Awaiting Analysis
    Oct 22, 2026 · NIST National Vulnerability Database
  • Source status changed · Published → Received
    Oct 21, 2026 · NIST National Vulnerability Database
  • Record published
    Oct 21, 2026
  • CVSS changed · 8.7
    Oct 21, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Published
    Oct 21, 2026 · CVE Program (cve.org) e CISA ADP
  • Record created in this database
    Oct 21, 2026 · CVE Program (cve.org) e CISA ADP
  • CVE published
    Oct 21, 2026 · apache

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 22, 2026 – Oct 22, 2026
  • 1× Official description updated · Oct 21, 2026 – Oct 21, 2026

References

3 on the record

Elsewhere on this site

Apache Software Foundation
every CVE for this vendor
Injection
same class
CWE-444
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-112381 Apache Traffic Server: Nullptr dereference in net_write_io on a POST half-close with chunked response 10d
  • CVE-2026-111812 Apache Traffic Server: origin_server_auth signs client-controlled AWS headers under the proxy's IAM credentials 10d
  • CVE-2026-111814 Apache Traffic Server: Default server_session_sharing.match omits MASK_CERT, allowing pooled mTLS identity confusion at the origin 10d
  • CVE-2026-111817 Apache Traffic Server: Dropping chunked trailers stalls a passthrough transfer until timeout 10d
  • CVE-2026-111815 Apache Traffic Server: TLS session ticket resumption bypasses per-SNI verify_client STRICT enforcement 10d
  • CVE-2026-111808 Apache Traffic Server: HTTP/2 DATA frame padding underflow lets a client trigger backend worker-pool exhaustion 10d

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 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-2025-55702 is "Apache Traffic Server: An unread Expect: 100-continue request body is framed as a new request", rated High. 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 8.7 describes technical severity. EPSS 0.33% estimates the probability of exploitation in 30 days; neither replaces your asset context. 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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