AEADs/aes-gcm: Plaintext exposed in decrypt_in_place_detached even on tag verification failure

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aes-gcm is a pure Rust implementation of the AES-GCM. Starting in version 0.10.0 and prior to version 0.10.3, in the AES GCM implementation of decrypt_in_place_detached, the decrypted ciphertext (i.e. the correct plaintext) is exposed even if tag verification fails. If a program using the `aes-gcm` crate's `decrypt_in_place*` APIs accesses the buffer after decryption failure, it will contain a decryption of an unauthenticated input. Depending on the specific nature of the program this may enable Chosen Ciphertext Attacks (CCAs) which can cause a catastrophic breakage of the cipher including full plaintext recovery. Version 0.10.3 contains a fix for this issue.

Source published

22 Sep 2023 15:19:15 UTC

Source modified

18 Jun 2025 14:22:56 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 4.7 CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:H/A:N

aes-gcm is a pure Rust implementation of the AES-GCM. Starting in version 0.10.0 and prior to version 0.10.3, in the AES GCM implementation of decrypt_in_place_detached, the decrypted ciphertext (i.e. the correct plaintext) is exposed even if tag verification fails. If a program using the `aes-gcm` crate's `decrypt_in_place*` APIs accesses the buffer after decryption failure, it will contain a decryption of an unauthenticated input. Depending on the specific nature of the program this may enable Chosen Ciphertext Attacks (CCAs) which can cause a catastrophic breakage of the cipher including full plaintext recovery. Version 0.10.3 contains a fix for this issue.

Source published

Sep 22, 2023, 3:19:15 PM (timezone not stated)

Source modified

Jun 18, 2025, 2:22:56 PM (timezone not stated)

Observed here

8 Nov 2026 23:03:48 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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EUVD CVSS 3.1 · 4.7 CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:H/A:N

aes-gcm is a pure Rust implementation of the AES-GCM. Starting in version 0.10.0 and prior to version 0.10.3, in the AES GCM implementation of decrypt_in_place_detached, the decrypted ciphertext (i.e. the correct plaintext) is exposed even if tag verification fails. If a program using the `aes-gcm` crate's `decrypt_in_place*` APIs accesses the buffer after decryption failure, it will contain a decryption of an unauthenticated input. Depending on the specific nature of the program this may enable Chosen Ciphertext Attacks (CCAs) which can cause a catastrophic breakage of the cipher including full plaintext recovery. Version 0.10.3 contains a fix for this issue.

Source published

22 Sep 2023 16:15:10 UTC

Source modified

17 Jun 2026 06:24:34 UTC

Observed here

24 Oct 2026 22:17:27 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 4.7 CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:H/A:N

CVSS 3.1 · [email protected] · Primary · 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

### Summary In the AES GCM implementation of decrypt_in_place_detached, the decrypted ciphertext (i.e. the correct plaintext) is exposed even if tag verification fails. ### Impact If a program using the `aes-gcm` crate's `decrypt_in_place*` APIs accesses the buffer after decryption failure, it will contain a decryption of an unauthenticated input. Depending on the specific nature of the program this may enable Chosen Ciphertext Attacks (CCAs) which can cause a catastrophic breakage of the cipher including full plaintext recovery. ### Details As seen in the implementation of [decrypt_in_place_detached](https://docs.rs/aes-gcm/latest/src/aes_gcm/lib.rs.html#309) for AES GCM, if the tag verification fails, an error is returned. Because the decryption of the ciphertext is done in place, the plaintext contents are now exposed via `buffer`. This should ideally not be the case - as noted in page 17 of[ NIST's publication _Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC_](https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38d.pdf): _In Step 8, the result of Step 7 is compared with the authentication tag that was received as an input: if they are identical, then the plaintext is returned; otherwise,FAIL is returned._ This is seems correctly addressed in the [AES GCM SIV implementation](https://docs.rs/aes-gcm-siv/latest/src/aes_gcm_siv/lib.rs.html#307), where the decrypted buffer is encrypted again before the error is returned - this fix is straightforward to implement in AES GCM. To ensure that these types of cases are covered during testing, it would be valuable to add test cases like [23, 24 ](https://github.com/google/wycheproof/blob/master/testvectors/aes_gcm_test.json#L288)etc from [project wycheproof ](https://github.com/google/wycheproof)to ensure that when a bad tag is used, there is an error on decryption _**and**_ that the plaintext value is not exposed. ### PoC To reproduce this issue, I'm using [test case 23](https://github.com/google/wycheproof/blob/master/testvectors/aes_gcm_test.json#L288) from project wycheproof. ```rust let key = GenericArray::from_slice(&hex!("000102030405060708090a0b0c0d0e0f")); let nonce = GenericArray::from_slice(&hex!("505152535455565758595a5b")); let tag = GenericArray::from_slice(&hex!("d9847dbc326a06e988c77ad3863e6083")); // bad tag let mut ct = hex!("eb156d081ed6b6b55f4612f021d87b39"); let msg = hex!("202122232425262728292a2b2c2d2e2f"); let aad = hex!(""); let cipher = Aes128Gcm::new(&key); let _plaintext = cipher.decrypt_in_place_detached(&nonce, &aad, &mut ct, &tag); assert_eq!(ct, msg); ```

Source published

22 Sep 2023 16:11:47 UTC

Source modified

3 Feb 2026 03:15:54 UTC

Observed here

24 Oct 2026 13:19:54 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:H/A:N

Publisher rating · MODERATE

## Summary In the AES GCM implementation of decrypt_in_place_detached, the decrypted ciphertext (i.e. the correct plaintext) is exposed even if tag verification fails. ## Impact If a program using the aes-gcm crate's decrypt_in_place* APIs accesses the buffer after decryption failure, it will contain a decryption of an unauthenticated input. Depending on the specific nature of the program this may enable Chosen Ciphertext Attacks (CCAs) which can cause a catastrophic breakage of the cipher including full plaintext recovery. ## Details As seen in the implementation of decrypt_in_place_detached for AES GCM, if the tag verification fails, an error is returned. Because the decryption of the ciphertext is done in place, the plaintext contents are now exposed via buffer. This should ideally not be the case - as noted in page 17 of NIST's publication Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC: In Step 8, the result of Step 7 is compared with the authentication tag that was received as an input: if they are identical, then the plaintext is returned; otherwise,FAIL is returned. This is seems correctly addressed in the AES GCM SIV implementation, where the decrypted buffer is encrypted again before the error is returned - this fix is straightforward to implement in AES GCM. To ensure that these types of cases are covered during testing, it would be valuable to add test cases like 23, 24 etc from project wycheproof to ensure that when a bad tag is used, there is an error on decryption and that the plaintext value is not exposed. ## PoC To reproduce this issue, I'm using test case 23 from project wycheproof. ``` let key = GenericArray::from_slice(&hex!("000102030405060708090a0b0c0d0e0f")); let nonce = GenericArray::from_slice(&hex!("505152535455565758595a5b")); let tag = GenericArray::from_slice(&hex!("d9847dbc326a06e988c77ad3863e6083")); // bad tag let mut ct = hex!("eb156d081ed6b6b55f4612f021d87b39"); let msg = hex!("202122232425262728292a2b2c2d2e2f"); let aad = hex!(""); let cipher = Aes128Gcm::new(&key); let _plaintext = cipher.decrypt_in_place_detached(&nonce, &aad, &mut ct, &tag); assert_eq!(ct, msg); ```

Source published

22 Nov 2023 12:00:00 UTC

Source modified

12 Oct 2026 18:00:05 UTC

Observed here

24 Oct 2026 13:19:54 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:H/A:N