CVE-2026-40194

phpseclib is a PHP secure communications library. Starting in 0.1.1 and prior to 3.0.51, 2.0.53, and 1.0.28, phpseclib\Net\SSH2::get_binary_packet() uses PHP's != operator to compare a received SSH packet HMAC against the locally computed HMAC. != on equal-length binary strings in PHP uses memcmp(), which short-circuits on the first differing byte. This is a real variable-time comparison (CWE-208), proven by scaling benchmarks. This vulnerability is fixed in 3.0.51, 2.0.53, and 1.0.28.

Database specific

{
    "cna_assigner":  "GitHub_M",
    "cwe_ids":  [
        "CWE-208"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40194.json"
}

References

Affected packages

Git / github.com/phpseclib/phpseclib

Affected ranges

Type

GIT

Repo

https://github.com/phpseclib/phpseclib

Events

Introduced

a8e70cbaa54234d466afdbf6d15d7af1751ce3eb

Fixed

8e2adfd761c11421ff4f4b694b4d0db78f3b4355

Introduced

a74aa9efbe61430fcb60157c8e025a48ec8ff604

Fixed

2d1a664b940b9b8f367185307dc010d11a2790f3

Introduced

fe62c85e0203503231d489af95d0ac053b7d3575

Fixed

d59c94077f9c9915abb51ddb52ce85188ece1748

Fixed

ffe48b6b1b1af6963327f0a5330e3aa004a194ac

Database specific

Show details

{
    "extracted_events":  [
        {
            "range":  [
                {
                    "introduced":  "0.1.1"
                },
                {
                    "fixed":  "1.0.28"
                }
            ],
            "source":  "AFFECTED_FIELD",
            "strategy":  "StringRangeExpression"
        },
        {
            "range":  [
                {
                    "introduced":  "2.0.0"
                },
                {
                    "fixed":  "2.0.53"
                }
            ],
            "source":  "AFFECTED_FIELD",
            "strategy":  "StringRangeExpression"
        },
        {
            "range":  [
                {
                    "introduced":  "3.0.0"
                },
                {
                    "fixed":  "3.0.51"
                }
            ],
            "source":  "AFFECTED_FIELD",
            "strategy":  "StringRangeExpression"
        },
        {
            "range":  [
                {
                    "fixed":  "ffe48b6b1b1af6963327f0a5330e3aa004a194ac"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        },
        {
            "original_tag":  "1.0.28",
            "range":  [
                {
                    "fixed":  "8e2adfd761c11421ff4f4b694b4d0db78f3b4355"
                }
            ],
            "source":  "REFERENCES_TAG"
        },
        {
            "original_tag":  "2.0.53",
            "range":  [
                {
                    "fixed":  "2d1a664b940b9b8f367185307dc010d11a2790f3"
                }
            ],
            "source":  "REFERENCES_TAG"
        },
        {
            "original_tag":  "3.0.51",
            "range":  [
                {
                    "fixed":  "d59c94077f9c9915abb51ddb52ce85188ece1748"
                }
            ],
            "source":  "REFERENCES_TAG"
        }
    ]
}

Affected versions

0.*

0.1.1

0.1.2

0.1.5

0.2.0

0.2.1

0.2.2

0.3.0

0.3.6

0.3.7

0.3.8

1.*

1.0.1

1.0.10

1.0.11

1.0.12

1.0.13

1.0.14

1.0.15

1.0.16

1.0.17

1.0.18

1.0.19

1.0.20

1.0.21

1.0.22

1.0.23

1.0.24

1.0.25

1.0.26

1.0.27

1.0.4

1.0.5

1.0.6

1.0.7

1.0.8

1.0.9

2.*

2.0.0

2.0.10

2.0.11

2.0.12

2.0.13

2.0.14

2.0.15

2.0.16

2.0.17

2.0.18

2.0.19

2.0.20

2.0.21

2.0.22

2.0.23

2.0.24

2.0.25

2.0.26

2.0.27

2.0.28

2.0.29

2.0.3

2.0.30

2.0.31

2.0.32

2.0.33

2.0.34

2.0.35

2.0.36

2.0.37

2.0.38

2.0.39

2.0.4

2.0.40

2.0.41

2.0.42

2.0.43

2.0.44

2.0.45

2.0.46

2.0.47

2.0.48

2.0.49

2.0.5

2.0.50

2.0.51

2.0.52

2.0.6

2.0.7

2.0.9

3.*

3.0.0

3.0.1

3.0.10

3.0.11

3.0.12

3.0.13

3.0.14

3.0.15

3.0.16

3.0.17

3.0.18

3.0.19

3.0.2

3.0.20

3.0.21

3.0.22

3.0.23

3.0.3

3.0.33

3.0.34

3.0.35

3.0.36

3.0.37

3.0.38

3.0.39

3.0.4

3.0.40

3.0.41

3.0.42

3.0.43

3.0.44

3.0.45

3.0.46

3.0.47

3.0.48

3.0.49

3.0.5

3.0.50

3.0.6

3.0.7

3.0.8

3.0.9

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-40194.json"