VulnerabilityPublished 19 Feb 2026

CVE-2026-26275: junkurihara httpsig-rs · Improper Validation of Integrity Check Value

Affects junkurihara httpsig-rsSource CVE Database V5

Not known to be exploited · CVSS 7.5 High : upgrade to 0.0.23 soon.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.0.23

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: High
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: 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: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to 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 19 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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 junkurihara httpsig-rs to 0.0.23.

Affected software

Product	Affected	Fixed in
junkuriharahttpsig-rs	Affected <0.0.23	Fixed in 0.0.23

AI-suggested

The primary mitigation is to upgrade httpsig-hyper to version 0.0.23 or later, which contains the fix for this vulnerability. Until upgrading is possible, organizations should avoid relying solely on Digest header verification for message integrity. Instead, enforce full HTTP message signature validation at the application layer, including verification of signature headers beyond the Digest. Implement defense-in-depth by combining multiple integrity checks and monitoring for anomalous message modifications. Review and audit code that depends on httpsig-rs to ensure no insecure assumptions about digest verification exist. Employ constant-time comparison techniques where applicable to prevent timing attacks. Additionally, conduct regression testing after upgrades to confirm the vulnerability is resolved and not reintroduced. Maintain awareness of updates from the vendor and monitor for any emerging exploits targeting this vulnerability.

Description

httpsig-hyper is a hyper extension for http message signatures. An issue was discovered in `httpsig-hyper` prior to version 0.0.23 where Digest header verification could incorrectly succeed due to misuse of Rust's `matches!` macro. Specifically, the comparison `if matches!(digest, _expected_digest)` treated `_expected_digest` as a pattern binding rather than a value comparison, resulting in unconditional success of the match expression. As a consequence, digest verification could incorrectly return success even when the computed digest did not match the expected value. Applications relying on Digest verification as part of HTTP message signature validation may therefore fail to detect message body modification. The severity depends on how the library is integrated and whether additional signature validation layers are enforced. This issue has been fixed in `httpsig-hyper` 0.0.23. The fix replaces the incorrect `matches!` usage with proper value comparison and additionally introduces constant-time comparison for digest verification as defense-in-depth. Regression tests have also been added to prevent reintroduction of this issue. Users are strongly advised to upgrade to the patched version. There is no reliable workaround without upgrading. Users who cannot immediately upgrade should avoid relying solely on Digest verification for message integrity and ensure that full HTTP message signature verification is enforced at the application layer.

Impact

This vulnerability compromises the integrity of HTTP message signature verification in applications using vulnerable versions of httpsig-hyper. Attackers can modify HTTP message bodies without detection, potentially enabling message forgery, replay attacks, or injection of malicious content. This can lead to unauthorized actions, data corruption, or bypass of security controls relying on message integrity. Since the flaw allows unconditional digest verification success, it undermines trust in signed HTTP communications, affecting APIs, microservices, and distributed systems that depend on httpsig-rs for secure message validation. The impact is particularly severe in environments where Digest verification is the sole integrity check. Although availability and confidentiality are not directly affected, the integrity breach can facilitate further attacks compromising these properties. Organizations worldwide using Rust-based HTTP signature libraries or frameworks that incorporate httpsig-rs are at risk until patched.

Summary

The vulnerability CVE-2026-26275 affects the httpsig-hyper Rust library (httpsig-rs) used for HTTP message signature verification. The root cause is the incorrect use of Rust's matches! macro in digest verification logic. Specifically, the code snippet `if matches!(digest, _expected_digest)` mistakenly treats `_expected_digest` as a pattern binding rather than performing a value equality check. This results in the match expression always evaluating to true, causing the Digest header verification to succeed unconditionally. Consequently, applications relying on this library's Digest verification may accept tampered HTTP message bodies without detection, undermining message integrity. The flaw is classified under CWE-354 (Improper Validation of Integrity Check Value) and CWE-697 (Incorrect Comparison). The fix implemented in version 0.0.23 replaces the matches! macro with a proper equality comparison and introduces constant-time comparison to prevent timing attacks. Regression tests were added to prevent recurrence. The vulnerability is exploitable remotely without authentication or user interaction, impacting the integrity of HTTP message signatures. No known exploits are reported in the wild yet. The severity depends on how the library is integrated and whether additional signature validation layers are in place.

CWE-354Improper Validation of Integrity Check Value (opens in a new tab)
Base weaknessLikelihood of exploit: Medium
The product does not validate or incorrectly validates the integrity check values or "checksums" of a message. This may prevent it from detecting if the data has been modified or corrupted in transmission.
Implementation
Ensure that the checksums present in messages are properly checked in accordance with the protocol specification before they are parsed and used.
OWASP Cheat Sheets
XML Security (opens in a new tab)
REST Security (opens in a new tab)
JSON Web Token for Java (opens in a new tab)
OWASP ASVS 4.0.3
V11.1.7 (opens in a new tab)
V13.3.2 (opens in a new tab)
V3.5.3 (opens in a new tab)
Attack patterns
Checksum Spoofing (opens in a new tab)
Padding Oracle Crypto Attack (opens in a new tab)
Manipulating Writeable Configuration Files (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-697Incorrect Comparison (opens in a new tab)
Pillar weakness
The product compares two entities in a security-relevant context, but the comparison is incorrect.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Attack patterns
Buffer Overflow via Environment Variables (opens in a new tab)
Double Encoding (opens in a new tab)
Client-side Injection-induced Buffer Overflow (opens in a new tab)
Command Delimiters (opens in a new tab)
Flash Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Feb 2026, 14:46 UTC

WeaknessesCWE-354, CWE-697

Technical details

References

Community reviews

Related threats