VulnerabilityPublished 13 Aug 2026Updated 29 Oct 2026

CVE-2026-49853: Tornado · Authorization header forwarded across cross-origin redirects in SimpleAsyncHTTPClient

Affects livereloadSource GCVE Database

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Not known to be exploited · CVSS 7.7 High : upgrade to 2.7.1_2 soon.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score

7.7High

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.7.1_2

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

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

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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Aug 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 livereload to 2.7.1_2.

Affected software

Product	Affected	Fixed in
Homebrewlivereload`pkg:brew/livereload`Other threats	Affected >=2.7.1 <2.7.1_2	Fixed in 2.7.1_2

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

AI-suggested

Upgrade Tornado to version 2.7.1_2 or later, where the issue is fixed by removing Authorization and Cookie headers on cross-origin redirects. No additional mitigation is required once the patch is applied.

Description

A vulnerability in Tornado's SimpleAsyncHTTPClient allows the Authorization header to be forwarded across cross-origin redirects. When following 3xx redirects, the client does not clear sensitive authentication headers if the redirect target changes origin, potentially exposing credentials to unintended hosts. This behavior was corrected starting with Tornado version 2.7.1_2, which removes Authorization and Cookie headers on cross-origin redirects by default.

Impact

An attacker controlling a redirect target could receive Authorization credentials intended for a different origin, leading to credential leakage. The vulnerability has a CVSS 3.1 score of 7.7 (high severity) with network attack vector, low attack complexity, requiring privileges and no user interaction, impacting confidentiality but not integrity or availability.

Summary

SimpleAsyncHTTPClient in Tornado versions >=2.7.1 and <2.7.1_2 improperly handles HTTP 3xx redirects by shallow-copying the original HTTPRequest and only removing the Host header, leaving Authorization, auth_username, auth_password, and auth_mode headers intact even when the redirect target changes origin. This can cause credentials intended for one origin to be sent to a different origin when follow_redirects is enabled (default true). The issue was fixed in version 2.7.1_2 by aligning behavior with libcurl, removing Authorization and Cookie headers when the scheme, host, or port changes during a redirect.

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What to do

Affected software

Description

AI analysisMachine-generated, updated 30 Oct 2026, 06:59 UTC

Technical details

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