Exploited: 178
LatestCVE-2026-115731 — Report Deserialization Code Execution
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7.5
CVE-2026-118782Fix available

Forge: PKCS#12 MAC forgery and constant-key PBE via zero iteration count

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Summary

### Summary forge.pkcs12.pkcs12FromAsn1() accepts a PKCS#12 MAC iteration count of zero (or less) from the input, and the PKCS#12 key derivation function then returns a constant key that does not depend on the password or salt. An attacker who does not know the password can modify a PKCS#12/PFX file and compute a MAC that verifies with any password; PKCS#12 PBE-encrypted private keys prepared the same way decrypt with any password. Fixed in node-forge 1.4.1. ### Details `p12.pkcs12FromAsn1()` in `lib/pkcs12.js` reads the MAC iteration count (`MacData.iterations`) from the input and passes it to the PKCS#12 key derivation function `pki.pbe.generatePkcs12Key()` in `lib/pbe.js` (also exposed as `forge.pkcs12.generateKey()`) without checking that it is at least 1. The key derivation function (RFC 7292 Appendix B.2) runs its hash loop `iter` times. With an iteration count of 0 (or an empty or negative INTEGER), no hashing is done and the function returns the PKCS#12 diversifier ID byte repeated, for example `0x03` repeated 20 times for an HMAC-SHA1 MAC key. The result does not depend on the password or the salt, so anyone can compute a valid MAC over arbitrary PFX contents. The same key derivation function is used by `pki.pbe.getCipherForPKCS12PBE()` for the PKCS#12 password-based encryption schemes `pbeWithSHAAnd3-KeyTripleDES-CBC` and `pbewithSHAAnd40BitRC2-CBC`, whose `pkcs-12PbeParams` iteration count is also read from the input. With an iteration count of 0 or less, the encryption key and IV are constants (`0x01` and `0x02` repeated). This is reached from shrouded key bags and encrypted SafeContents in `pkcs12FromAsn1()`, and from `forge.pki.decryptPrivateKeyInfo()` (for example for `ENCRYPTED PRIVATE KEY` PEM input). RFC 7292 defines `MacData` with `iterations INTEGER DEFAULT 1`; an iteration count only makes sense as 1 or more (RFC 8018 uses `INTEGER (1..MAX)` for the same concept). PBES2 (PBKDF2) encrypted content is not affected. The fix rejects iteration count…

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