VulnerabilityPublished 23 Oct 2026Updated 29 Oct 2026

CVE-2026-114603: OpenTelemetry Python · Unbounded tracestate parsing in opentelemetry-api

Affects mcp-atlassianSource GCVE Database

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Authoritative record:CVE-2026-114603· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium : upgrade to 0.23.1_2 when convenient.

Data as of 30 Oct 2026, 08:17 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (GitHub_M)	CVSS 3.1	5.3

Patch: Available – fixed in 0.23.1_2

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade mcp-atlassian to 0.23.1_2.

Affected software

Product	Affected	Fixed in
Homebrewmcp-atlassian`pkg:brew/mcp-atlassian`Other threats	Affected >=0.11.11 <0.23.1_2	Fixed in 0.23.1_2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available in opentelemetry-api version 0.23.1_2. Users should upgrade to this version or later to mitigate the vulnerability. Until patched, users can consider limiting the maximum allowed size of tracestate headers at the server or proxy level to reduce the risk of exploitation. The sibling baggage propagator's approach of rejecting headers exceeding 8192 bytes is a recommended pattern to apply for tracestate headers as well.

Description

A vulnerability in the OpenTelemetry Python package (opentelemetry-api) affects the TraceState.from_header method, which parses the W3C tracestate header. The parsing uses a regular expression with an unbounded optional whitespace run and no length limit, causing an O(N²) CPU cost on inputs with long runs of spaces or tabs without commas. This can lead to significant CPU consumption and blocking of request handling, especially under asyncio servers. The issue has been confirmed in versions from 1.0.0 through v1.45.0 and is fixed in version 0.23.1_2.

Impact

An attacker can send a specially crafted tracestate header with a large run of spaces or tabs to cause excessive CPU consumption due to quadratic regex parsing time. This can block the handling worker for several seconds (up to ~12 seconds for ~100 KB headers), effectively causing a denial of service by delaying or blocking other requests on the server. The vulnerability affects availability but does not impact confidentiality or integrity. No authentication is required to exploit this issue.

Summary

The vulnerability arises from the TraceState.from_header method in opentelemetry-api, which splits the inbound tracestate header using a regex pattern that starts with an unbounded optional whitespace run ([ \t]*). When the header contains a long sequence of spaces or tabs without commas, the regex engine exhibits quadratic time complexity (O(N²)) due to repeated backtracking. This causes excessive CPU usage and delays in processing, blocking other connections in asynchronous servers. The issue is present in versions from 1.0.0 through v1.45.0 and has been fixed in version 0.23.1_2. The vulnerability can be triggered by unauthenticated requests with large tracestate headers (~100 KB), causing processing delays of several seconds per request. The sibling baggage propagator already implements a length check to mitigate similar issues, but tracestate parsing lacked such a guard until the fix.

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Description

AI analysisMachine-generated, updated 30 Oct 2026, 08:17 UTC

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