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CVE-2017-18122· NVD / CVE Program· CNA mitre

A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16.

A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.

HighCVSS 8.1 · v3.0—No exploit Fix available
Published
Feb 2, 2018
Updated
Jun 16, 2026
EPSS
1.1% · 64th percentile
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Report tools

JSON

Action score

32

Monitor

Low priority for now.

CVSS
32 / 40 · 8.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.1%

Affected systems

VendorProduct
simplesamlphpsimplesamlphp
debiandebian linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux7.0
  • debian debian linux8.0
  • debian debian linux9.0
  • simplesamlphp simplesamlphpup to 1.14.16 inclusive

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12simplesamlphpbefore 1.15.0-11.15.0-1
Debian:7simplesamlphpbefore 1.9.2-1+deb7u21.9.2-1+deb7u2
Debian:8simplesamlphpbefore 1.13.1-2+deb8u11.13.1-2+deb8u1
Debian:9simplesamlphpbefore 1.14.11-1+deb9u11.14.11-1+deb9u1
Packagistsimplesamlphp/simplesamlphpbefore 1.14.171.14.17

Same product

simplesamlphp: all records

Other highest-scoring records for the same primary product.

  • CVE-2018-6521The sqlauth module in SimpleSAMLphp before 1.15.2 relies on the MySQL utf8 charset, which truncates queries upon encountering four-byte char
    40Plan
  • CVE-2017-12868The secureCompare method in lib/SimpleSAML/Utils/Crypto.php in SimpleSAMLphp 1.14.13 and earlier, when used with PHP before 5.6, allows atta
    40Plan
  • CVE-2017-12873SimpleSAMLphp 1.7.0 through 1.14.10 might allow attackers to obtain sensitive information, gain unauthorized access, or have unspecified oth
    39Monitor
  • CVE-2016-9814The validateSignature method in the SAML2\Utils class in SimpleSAMLphp before 1.14.10 and simplesamlphp/saml2 library before 1.9.1, 1.10.x b
    37Monitor
  • CVE-2019-3465Rob Richards XmlSecLibs, all versions prior to v3.0.3, as used for example by SimpleSAMLphp, performed incorrect validation of cryptographic
    36Monitor
  • CVE-2018-7711HTTPRedirect.php in the saml2 library in SimpleSAMLphp before 1.15.4 has an incorrect check of return values in the signature validation uti
    32Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:simplesamlphp1.15.0-1 · Debian:12Package registry (OSV)
Packagist:simplesamlphp/simplesamlphp1.14.17Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-347 · Improper Verification of Cryptographic Signature

CVSS vector

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Root cause

The verifier takes the algorithm to verify with from the token’s own header. Untrusted data ends up deciding its own verification rule.

The bug in code

The whole CWE-347 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
const claims = jwt.verify(token, publicKey);

Fixed

ts
const claims = jwt.verify(token, publicKey, {  algorithms: ["RS256"],  issuer: "https://id.example.com",  audience: "portal",});

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records