static int crypto_ccm_decrypt(struct aead_request *req)
{
	struct crypto_aead *aead = crypto_aead_reqtfm(req);
	struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
	struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
	struct skcipher_request *skreq = &pctx->skreq;
	struct scatterlist *dst;
	unsigned int authsize = crypto_aead_authsize(aead);
	unsigned int cryptlen = req->cryptlen;
	u8 *authtag = pctx->auth_tag;
	u8 *odata = pctx->odata;
	u8 *iv = req->iv;
	int err;

	cryptlen -= authsize;

	err = crypto_ccm_init_crypt(req, authtag);
	if (err)
		return err;

	scatterwalk_map_and_copy(authtag, sg_next(pctx->src), cryptlen,
				 authsize, 0);

	dst = pctx->src;
	if (req->src != req->dst)
		dst = pctx->dst;

	skcipher_request_set_tfm(skreq, ctx->ctr);
	skcipher_request_set_callback(skreq, pctx->flags,
				      crypto_ccm_decrypt_done, req);
	skcipher_request_set_crypt(skreq, pctx->src, dst, cryptlen + 16, iv);
	err = crypto_skcipher_decrypt(skreq);
	if (err)
		return err;

	err = crypto_ccm_auth(req, sg_next(dst), cryptlen);
	if (err)
		return err;

	/* verify */
	if (crypto_memneq(authtag, odata, authsize))
		return -EBADMSG;

	return err;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.